[W3C] Document Object Model (DOM) Level 2 Traversal and Range Specification Version 1.0 W3C Recommendation 13 November, 2000 This version: http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113 ( PostScript file , PDF file , plain text , ZIP file) Latest version: http://www.w3.org/TR/DOM-Level-2-Traversal-Range Previous version: http://www.w3.org/TR/2000/PR-DOM-Level-2-Traversal-Range-20000927 Editors: Joe Kesselman, IBM Jonathan Robie, Texcel Research and Software AG Mike Champion, Arbortext and Software AG Peter Sharpe, SoftQuad Software Inc. Vidur Apparao, Netscape Communications Corp. Lauren Wood, SoftQuad Software Inc., WG Chair Copyright © 2000 W3C® (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply. ---------------------------------------------------------------------------- Abstract This specification defines the Document Object Model Level 2 Traversal and Range, platform- and language-neutral interfaces that allow programs and scripts to dynamically traverse and identify a range of content in a document. The Document Object Model Level 2 Traversal and Range build on the Document Object Model Level 2 Core [DOM Level 2 Core]. The DOM Level 2 Traversal and Range specification is composed of two modules. The two modules contain specialized interfaces dedicated to traversing the document structure and identifying and manipulating a range in a document. Status of this document This section describes the status of this document at the time of its publication. Other documents may supersede this document. The latest status of this document series is maintained at the W3C. This document has been reviewed by W3C Members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web. This document has been produced as part of the W3C DOM Activity. The authors of this document are the DOM Working Group members. Different modules of the Document Object Model have different editors. Please send general comments about this document to the public mailing list www-dom@w3.org. An archive is available at http://lists.w3.org/Archives/Public/www-dom/. The English version of this specification is the only normative version. Information about translations of this document is available at http://www.w3.org/2000/11/DOM-Level-2-translations. The list of known errors in this document is available at http://www.w3.org/2000/11/DOM-Level-2-errata A list of current W3C Recommendations and other technical documents can be found at http://www.w3.org/TR. Table of contents * Expanded Table of Contents * Copyright Notice * Chapter 1: Document Object Model Traversal * Chapter 2: Document Object Model Range * Appendix A: IDL Definitions * Appendix B: Java Language Binding * Appendix C: ECMAScript Language Binding * Appendix D: Acknowledgements * Glossary * References * Index 13 November, 2000 Expanded Table of Contents * Expanded Table of Contents * Copyright Notice o W3C Document Copyright Notice and License o W3C Software Copyright Notice and License * Chapter 1: Document Object Model Traversal o 1.1. Overview + 1.1.1. NodeIterators + 1.1.2. NodeFilters + 1.1.3. TreeWalker o 1.2. Formal Interface Definition * Chapter 2: Document Object Model Range o 2.1. Introduction o 2.2. Definitions and Notation + 2.2.1. Position + 2.2.2. Selection and Partial Selection + 2.2.3. Notation o 2.3. Creating a Range o 2.4. Changing a Range's Position o 2.5. Comparing Range Boundary-Points o 2.6. Deleting Content with a Range o 2.7. Extracting Content o 2.8. Cloning Content o 2.9. Inserting Content o 2.10. Surrounding Content o 2.11. Miscellaneous Members o 2.12. Range modification under document mutation + 2.12.1. Insertions + 2.12.2. Deletions o 2.13. Formal Description of the Range Interface * Appendix A: IDL Definitions o A.1. Document Object Model Traversal o A.2. Document Object Model Range * Appendix B: Java Language Binding o B.1. Document Object Model Traversal o B.2. Document Object Model Range * Appendix C: ECMAScript Language Binding o C.1. Document Object Model Traversal o C.2. Document Object Model Range * Appendix D: Acknowledgements o D.1. Production Systems * Glossary * References o 1. Normative references * Index 13 November, 2000 Copyright Notice Copyright © 2000 World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de Recherche en Informatique et en Automatique, Keio University). All Rights Reserved. This document is published under the W3C Document Copyright Notice and License. The bindings within this document are published under the W3C Software Copyright Notice and License. The software license requires "Notice of any changes or modifications to the W3C files, including the date changes were made." 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Document Object Model Traversal Editors Joe Kesselman, IBM Jonathan Robie, Software AG Mike Champion, Software AG Table of contents * 1.1. Overview o 1.1.1. NodeIterators o 1.1.2. NodeFilters o 1.1.3. TreeWalker * 1.2. Formal Interface Definition o NodeIterator, NodeFilter, TreeWalker, DocumentTraversal 1.1. Overview This chapter describes the optional DOM Level 2 Traversal feature. Its TreeWalker, NodeIterator, and NodeFilter interfaces provide easy-to-use, robust, selective traversal of a document's contents. The interfaces found within this section are not mandatory. A DOM application may use the hasFeature(feature, version) method of the DOMImplementation interface with parameter values "Traversal" and "2.0" (respectively) to determine whether or not this module is supported by the implementation. In order to fully support this module, an implementation must also support the "Core" feature defined defined in the DOM Level 2 Core specification [DOM Level 2 Core]. Please refer to additional information about conformance in the DOM Level 2 Core specification [DOM Level 2 Core]. NodeIterators and TreeWalkers are two different ways of representing the nodes of a document subtree and a position within the nodes they present. A NodeIterator presents a flattened view of the subtree as an ordered sequence of nodes, presented in document order. Because this view is presented without respect to hierarchy, iterators have methods to move forward and backward, but not to move up and down. Conversely, a TreeWalker maintains the hierarchical relationships of the subtree, allowing navigation of this hierarchy. In general, TreeWalkers are better for tasks in which the structure of the document around selected nodes will be manipulated, while NodeIterators are better for tasks that focus on the content of each selected node. NodeIterators and TreeWalkers each present a view of a document subtree that may not contain all nodes found in the subtree. In this specification, we refer to this as the logical view to distinguish it from the physical view, which corresponds to the document subtree per se. When an iterator or TreeWalker is created, it may be associated with a NodeFilter, which examines each node and determines whether it should appear in the logical view. In addition, flags may be used to specify which node types should occur in the logical view. NodeIterators and TreeWalkers are dynamic - the logical view changes to reflect changes made to the underlying document. However, they differ in how they respond to those changes. NodeIterators, which present the nodes sequentially, attempt to maintain their location relative to a position in that sequence when the sequence's contents change. TreeWalkers, which present the nodes as a filtered tree, maintain their location relative to their current node and remain attached to that node if it is moved to a new context. We will discuss these behaviors in greater detail below. 1.1.1. NodeIterators A NodeIterator allows the members of a list of nodes to be returned sequentially. In the current DOM interfaces, this list will always consist of the nodes of a subtree, presented in document order. When an iterator is first created, calling its nextNode() method returns the first node in the logical view of the subtree; in most cases, this is the root of the subtree. Each successive call advances the NodeIterator through the list, returning the next node available in the logical view. When no more nodes are visible, nextNode() returns null. NodeIterators are created using the createNodeIterator method found in the DocumentTraversal interface. When a NodeIterator is created, flags can be used to determine which node types will be "visible" and which nodes will be "invisible" while traversing the tree; these flags can be combined using the OR operator. Nodes that are "invisible" are skipped over by the iterator as though they did not exist. The following code creates an iterator, then calls a function to print the name of each element: NodeIterator iter= ((DocumentTraversal)document).createNodeIterator( root, NodeFilter.SHOW_ELEMENT, null); while (Node n = iter.nextNode()) printMe(n); 1.1.1.1. Moving Forward and Backward NodeIterators present nodes as an ordered list, and move forward and backward within this list. The iterator's position is always either between two nodes, before the first node, or after the last node. When an iterator is first created, the position is set before the first item. The following diagram shows the list view that an iterator might provide for a particular subtree, with the position indicated by an asterisk '*' : * A B C D E F G H I Each call to nextNode() returns the next node and advances the position. For instance, if we start with the above position, the first call to nextNode() returns "A" and advances the iterator: [A] * B C D E F G H I The position of a NodeIterator can best be described with respect to the last node returned, which we will call the reference node. When an iterator is created, the first node is the reference node, and the iterator is positioned before the reference node. In these diagrams, we use square brackets to indicate the reference node. A call to previousNode() returns the previous node and moves the position backward. For instance, if we start with the NodeIterator between "A" and "B", it would return "A" and move to the position shown below: * [A] B C D E F G H I If nextNode() is called at the end of a list, or previousNode() is called at the beginning of a list, it returns null and does not change the position of the iterator. When a NodeIterator is first created, the reference node is the first node: * [A] B C D E F G H I 1.1.1.2. Robustness A NodeIterator may be active while the data structure it navigates is being edited, so an iterator must behave gracefully in the face of change. Additions and removals in the underlying data structure do not invalidate a NodeIterator; in fact, a NodeIterator is never invalidated unless its detach() method is invoked. To make this possible, the iterator uses the reference node to maintain its position. The state of an iterator also depends on whether the iterator is positioned before or after the reference node. If changes to the iterated list do not remove the reference node, they do not affect the state of the NodeIterator. For instance, the iterator's state is not affected by inserting new nodes in the vicinity of the iterator or removing nodes other than the reference node. Suppose we start from the following position: A B C [D] * E F G H I Now let's remove "E". The resulting state is: A B C [D] * F G H I If a new node is inserted, the NodeIterator stays close to the reference node, so if a node is inserted between "D" and "F", it will occur between the iterator and "F": A B C [D] * X F G H I Moving a node is equivalent to a removal followed by an insertion. If we move "I" to the position before "X" the result is: A B C [D] * I X F G H If the reference node is removed from the list being iterated over, a different node is selected as the reference node. If the reference node's position is before that of the NodeIterator, which is usually the case after nextNode() has been called, the nearest node before the iterator is chosen as the new reference node. Suppose we remove the "D" node, starting from the following state: A B C [D] * F G H I The "C" node becomes the new reference node, since it is the nearest node to the NodeIterator that is before the iterator: A B [C] * F G H I If the reference node is after the NodeIterator, which is usually the case after previousNode() has been called, the nearest node after the iterator is chosen as the new reference node. Suppose we remove "E", starting from the following state: A B C D * [E] F G H I The "F" node becomes the new reference node, since it is the nearest node to the NodeIterator that is after the iterator: A B C D * [F] G H I As noted above, moving a node is equivalent to a removal followed by an insertion. Suppose we wish to move the "D" node to the end of the list, starting from the following state: A B C [D] * F G H I C The resulting state is as follows: A B [C] * F G H I D One special case arises when the reference node is the last node in the list and the reference node is removed. Suppose we remove node "C", starting from the following state: A B * [C] According to the rules we have given, the new reference node should be the nearest node after the NodeIterator, but there are no further nodes after "C". The same situation can arise when previousNode() has just returned the first node in the list, which is then removed. Hence: If there is no node in the original direction of the reference node, the nearest node in the opposite direction is selected as the reference node: A [B] * If the NodeIterator is positioned within a block of nodes that is removed, the above rules clearly indicate what is to be done. For instance, suppose "C" is the parent node of "D", "E", and "F", and we remove "C", starting with the following state: A B C [D] * E F G H I D The resulting state is as follows: A [B] * G H I D Finally, note that removing a NodeIterator's root node from its parent does not alter the list being iterated over, and thus does not change the iterator's state. 1.1.1.3. Visibility of Nodes The underlying data structure that is being iterated may contain nodes that are not part of the logical view, and therefore will not be returned by the NodeIterator. If nodes that are to be excluded because of the value of the whatToShow flag, nextNode() returns the next visible node, skipping over the excluded "invisible" nodes. If a NodeFilter is present, it is applied before returning a node; if the filter does not accept the node, the process is repeated until a node is accepted by the filter and is returned. If no visible nodes are encountered, a null is returned and the iterator is positioned at the end of the list. In this case, the reference node is the last node in the list, whether or not it is visible. The same approach is taken, in the opposite direction, for previousNode(). In the following examples, we will use lowercase letters to represent nodes that are in the data structure, but which are not in the logical view. For instance, consider the following list: A [B] * c d E F G A call to nextNode() returns E and advances to the following position: A B c d [E] * F G Nodes that are not visible may nevertheless be used as reference nodes if a reference node is removed. Suppose node "E" is removed, started from the state given above. The resulting state is: A B c [d] * F G Suppose a new node "X", which is visible, is inserted before "d". The resulting state is: A B c X [d] * F G Note that a call to previousNode() now returns node X. It is important not to skip over invisible nodes when the reference node is removed, because there are cases, like the one just given above, where the wrong results will be returned. When "E" was removed, if the new reference node had been "B" rather than "d", calling previousNode() would not return "X". 1.1.2. NodeFilters NodeFilters allow the user to create objects that "filter out" nodes. Each filter contains a user-written function that looks at a node and determines whether or not it should be presented as part of the traversal's logical view of the document. To use a NodeFilter, you create a NodeIterator or a TreeWalker that uses the filter. The traversal engine applies the filter to each node, and if the filter does not accept the node, traversal skips over the node as though it were not present in the document. NodeFilters need not know how to navigate the structure that contains the nodes on which they operate. Filters will be consulted when a traversal operation is performed, or when a NodeIterator's reference node is removed from the subtree being iterated over and it must select a new one. However, the exact timing of these filter calls may vary from one DOM implementation to another. For that reason, NodeFilters should not attempt to maintain state based on the history of past invocations; the resulting behavior may not be portable. Similarly, TreeWalkers and NodeIterators should behave as if they have no memory of past filter results, and no anticipation of future results. If the conditions a NodeFilter is examining have changed (e.g., an attribute which it tests has been added or removed) since the last time the traversal logic examined this node, this change in visibility will be discovered only when the next traversal operation is performed. For example: if the filtering for the current node changes from FILTER_SHOW to FILTER_SKIP, a TreeWalker will be able to navigate off that node in any direction, but not back to it unless the filtering conditions change again. NodeFilters which change during a traversal can be written, but their behavior may be confusing and they should be avoided when possible. 1.1.2.1. Using NodeFilters A NodeFilter contains one method named acceptNode(), which allows a NodeIterator or TreeWalker to pass a Node to a filter and ask whether it should be present in the logical view. The acceptNode() function returns one of three values to state how the Node should be treated. If acceptNode() returns FILTER_ACCEPT, the Node will be present in the logical view; if it returns FILTER_SKIP, the Node will not be present in the logical view, but the children of the Node may; if it returns FILTER_REJECT, neither the Node nor its descendants will be present in the logical view. Since iterators present nodes as an ordered list, without hierarchy, FILTER_REJECT and FILTER_SKIP are synonyms for NodeIterators, skipping only the single current node. Consider a filter that accepts the named anchors in an HTML document. In HTML, an HREF can refer to any A element that has a NAME attribute. Here is a NodeFilter in Java that looks at a node and determines whether it is a named anchor: class NamedAnchorFilter implements NodeFilter { short acceptNode(Node n) { if (n.getNodeType()==Node.ELEMENT_NODE) { Element e = (Element)n; if (! e.getNodeName().equals("A")) return FILTER_SKIP; if (e.getAttributeNode("NAME") != null) return FILTER_ACCEPT; } return FILTER_SKIP; } } If the above NodeFilter were to be used only with NodeIterators, it could have used FILTER_REJECT wherever FILTER_SKIP is used, and the behavior would not change. For TreeWalker, though, FILTER_REJECT would reject the children of any element that is not a named anchor, and since named anchors are always contained within other elements, this would have meant that no named anchors would be found. FILTER_SKIP rejects the given node, but continues to examine the children; therefore, the above filter will work with either a NodeIterator or a TreeWalker. To use this filter, the user would create an instance of the NodeFilter and create a NodeIterator using it: NamedAnchorFilter myFilter = new NamedAnchorFilter(); NodeIterator iter= ((DocumentTraversal)document).createNodeIterator( node, NodeFilter.SHOW_ELEMENT, myFilter); Note that the use of the SHOW_ELEMENT flag is not strictly necessary in this example, since our sample NodeFilter tests the nodeType. However, some implementations of the Traversal interfaces may be able to improve whatToShow performance by taking advantage of knowledge of the document's structure, which makes the use of SHOW_ELEMENT worthwhile. Conversely, while we could remove the nodeType test from our filter, that would make it dependent upon whatToShow to distinguish between Elements, Attr's, and ProcessingInstructions. 1.1.2.2. NodeFilters and Exceptions When writing a NodeFilter, users should avoid writing code that can throw an exception. However, because a DOM implementation can not prevent exceptions from being thrown, it is important that the behavior of filters that throw an exception be well-defined. A TreeWalker or NodeIterator does not catch or alter an exception thrown by a filter, but lets it propagate up to the user's code. The following functions may invoke a NodeFilter, and may therefore propagate an exception if one is thrown by a filter: 1. NodeIterator .nextNode() 2. NodeIterator .previousNode() 3. TreeWalker .firstChild() 4. TreeWalker .lastChild() 5. TreeWalker .nextSibling() 6. TreeWalker .previousSibling() 7. TreeWalker .nextNode() 8. TreeWalker .previousNode() 9. TreeWalker .parentNode() 1.1.2.3. NodeFilters and Document Mutation Well-designed NodeFilters should not have to modify the underlying structure of the document. But a DOM implementation can not prevent a user from writing filter code that does alter the document structure. Traversal does not provide any special processing to handle this case. For instance, if a NodeFilter removes a node from a document, it can still accept the node, which means that the node may be returned by the NodeIterator or TreeWalker even though it is no longer in the subtree being traversed. In general, this may lead to inconsistent, confusing results, so we encourage users to write NodeFilters that make no changes to document structures. Instead, do your editing in the loop controlled by the traversal object. 1.1.2.4. NodeFilters and whatToShow flags NodeIterator and TreeWalker apply their whatToShow flags before applying filters. If a node is skipped by the active whatToShow flags, a NodeFilter will not be called to evaluate that node. Please note that this behavior is similar to that of FILTER_SKIP; children of that node will be considered, and filters may be called to evaluate them. Also note that it will in fact be a "skip" even if the NodeFilter would have preferred to reject the entire subtree; if this would cause a problem in your application, consider setting whatToShow to SHOW_ALL and performing the nodeType test inside your filter. 1.1.3. TreeWalker The TreeWalker interface provides many of the same benefits as the NodeIterator interface. The main difference between these two interfaces is that the TreeWalker presents a tree-oriented view of the nodes in a subtree, rather than the iterator's list-oriented view. In other words, an iterator allows you to move forward or back, but a TreeWalker allows you to also move to the parent of a node, to one of its children, or to a sibling. Using a TreeWalker is quite similar to navigation using the Node directly, and the navigation methods for the two interfaces are analogous. For instance, here is a function that recursively walks over a tree of nodes in document order, taking separate actions when first entering a node and after processing any children: processMe(Node n) { nodeStartActions(n); for (Node child=n.firstChild(); child != null; child=child.nextSibling()) { processMe(child); } nodeEndActions(n); } Doing the same thing using a TreeWalker is quite similar. There is one difference: since navigation on the TreeWalker changes the current position, the position at the end of the function has changed. A read/write attribute named currentNode allows the current node for a TreeWalker to be both queried and set. We will use this to ensure that the position of the TreeWalker is restored when this function is completed: processMe(TreeWalker tw) { Node n = tw.getCurrentNode(); nodeStartActions(tw); for (Node child=tw.firstChild(); child!=null; child=tw.nextSibling()) { processMe(tw); } tw.setCurrentNode(n); nodeEndActions(tw); } The advantage of using a TreeWalker instead of direct Node navigation is that the TreeWalker allows the user to choose an appropriate view of the tree. Flags may be used to show or hide Comments or ProcessingInstructions; entities may be expanded or shown as EntityReference nodes. In addition, NodeFilters may be used to present a custom view of the tree. Suppose a program needs a view of a document that shows which tables occur in each chapter, listed by chapter. In this view, only the chapter elements and the tables that they contain are seen. The first step is to write an appropriate filter: class TablesInChapters implements NodeFilter { short acceptNode(Node n) { if (n.getNodeType()==Node.ELEMENT_NODE) { if (n.getNodeName().equals("CHAPTER")) return FILTER_ACCEPT; if (n.getNodeName().equals("TABLE")) return FILTER_ACCEPT; if (n.getNodeName().equals("SECT1") || n.getNodeName().equals("SECT2") || n.getNodeName().equals("SECT3") || n.getNodeName().equals("SECT4") || n.getNodeName().equals("SECT5") || n.getNodeName().equals("SECT6") || n.getNodeName().equals("SECT7")) return FILTER_SKIP; } return FILTER_REJECT; } } This filter assumes that TABLE elements are contained directly in CHAPTER or SECTn elements. If another kind of element is encountered, it and its children are rejected. If a SECTn element is encountered, it is skipped, but its children are explored to see if they contain any TABLE elements. Now the program can create an instance of this NodeFilter, create a TreeWalker that uses it, and pass this TreeWalker to our ProcessMe() function: TablesInChapters tablesInChapters = new TablesInChapters(); TreeWalker tw = ((DocumentTraversal)document).createTreeWalker( root, NodeFilter.SHOW_ELEMENT, tablesInChapters); processMe(tw); (Again, we've chosen to both test the nodeType in the filter's logic and use SHOW_ELEMENT, for the reasons discussed in the earlier NodeIterator example.) Without making any changes to the above ProcessMe() function, it now processes only the CHAPTER and TABLE elements. The programmer can write other filters or set other flags to choose different sets of nodes; if functions use TreeWalker to navigate, they will support any view of the document defined with a TreeWalker. Note that the structure of a TreeWalker's filtered view of a document may differ significantly from that of the document itself. For example, a TreeWalker with only SHOW_TEXT specified in its whatToShow parameter would present all the Text nodes as if they were siblings of each other yet had no parent. 1.1.3.1. Robustness As with NodeIterators, a TreeWalker may be active while the data structure it navigates is being edited, and must behave gracefully in the face of change. Additions and removals in the underlying data structure do not invalidate a TreeWalker; in fact, a TreeWalker is never invalidated. But a TreeWalker's response to these changes is quite different from that of a NodeIterator. While NodeIterators respond to editing by maintaining their position within the list that they are iterating over, TreeWalkers will instead remain attached to their currentNode. All the TreeWalker's navigation methods operate in terms of the context of the currentNode at the time they are invoked, no matter what has happened to, or around, that node since the last time the TreeWalker was accessed. This remains true even if the currentNode is moved out of its original subtree. As an example, consider the following document fragment: ... ... Let's say we have created a TreeWalker whose root node is the element and whose currentNode is the element. For this illustration, we will assume that all the nodes shown above are accepted by the TreeWalker's whatToShow and filter settings. If we use removeChild() to remove the element from its parent, that element remains the TreeWalker's currentNode, even though it is no longer within the root node's subtree. We can still use the TreeWalker to navigate through any children that the orphaned currentNode may have, but are no longer able to navigate outward from the currentNode since there is no parent available. If we use insertBefore() or appendChild() to give the a new parent, then TreeWalker navigation will operate from the currentNode's new location. For example, if we inserted the immediately after the element, the TreeWalker's previousSibling() operation would move it back to the , and calling parentNode() would move it up to the . If we instead insert the currentNode into the element, like so: ... ... we have moved the currentNode out from under the TreeWalker's root node. This does not invalidate the TreeWalker; it may still be used to navigate relative to the currentNode. Calling its parentNode() operation, for example, would move it to the element, even though that too is outside the original root node. However, if the TreeWalker's navigation should take it back into the original root node's subtree -- for example, if rather than calling parentNode() we called nextNode(), moving the TreeWalker to the element -- the root node will "recapture" the TreeWalker, and prevent it from traversing back out. This becomes a bit more complicated when filters are in use. Relocation of the currentNode -- or explicit selection of a new currentNode, or changes in the conditions that the NodeFilter is basing its decisions on -- can result in a TreeWalker having a currentNode which would not otherwise be visible in the filtered (logical) view of the document. This node can be thought of as a "transient member" of that view. When you ask the TreeWalker to navigate off this node the result will be just as if it had been visible, but you may be unable to navigate back to it unless conditions change to make it visible again. In particular: If the currentNode becomes part of a subtree that would otherwise have been Rejected by the filter, that entire subtree may be added as transient members of the logical view. You will be able to navigate within that subtree (subject to all the usual filtering) until you move upward past the Rejected ancestor. The behavior is as if the Rejected node had only been Skipped (since we somehow wound up inside its subtree) until we leave it; thereafter, standard filtering applies. 1.2. Formal Interface Definition Interface NodeIterator (introduced in DOM Level 2) Iterators are used to step through a set of nodes, e.g. the set of nodes in a NodeList, the document subtree governed by a particular Node, the results of a query, or any other set of nodes. The set of nodes to be iterated is determined by the implementation of the NodeIterator. DOM Level 2 specifies a single NodeIterator implementation for document-order traversal of a document subtree. Instances of these iterators are created by calling DocumentTraversal .createNodeIterator(). IDL Definition // Introduced in DOM Level 2: interface NodeIterator { readonly attribute Node root; readonly attribute unsigned long whatToShow; readonly attribute NodeFilter filter; readonly attribute boolean expandEntityReferences; Node nextNode() raises(DOMException); Node previousNode() raises(DOMException); void detach(); }; Attributes expandEntityReferences of type boolean, readonly The value of this flag determines whether the children of entity reference nodes are visible to the iterator. If false, they and their descendants will be rejected. Note that this rejection takes precedence over whatToShow and the filter. Also note that this is currently the only situation where NodeIterators may reject a complete subtree rather than skipping individual nodes. To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the iterator. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false. filter of type NodeFilter, readonly The NodeFilter used to screen nodes. root of type Node, readonly The root node of the NodeIterator, as specified when it was created. whatToShow of type unsigned long, readonly This attribute determines which node types are presented via the iterator. The available set of constants is defined in the NodeFilter interface. Nodes not accepted by whatToShow will be skipped, but their children may still be considered. Note that this skip takes precedence over the filter, if any. Methods detach Detaches the NodeIterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. After detach has been invoked, calls to nextNode or previousNode will raise the exception INVALID_STATE_ERR. No Parameters No Return Value No Exceptions nextNode Returns the next node in the set and advances the position of the iterator in the set. After a NodeIterator is created, the first call to nextNode() returns the first node in the set. Return Value Node The next Node in the set being iterated over, or null if there are no more members in that set. Exceptions DOMException INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked. No Parameters previousNode Returns the previous node in the set and moves the position of the NodeIterator backwards in the set. Return Value Node The previous Node in the set being iterated over, or null if there are no more members in that set. Exceptions DOMException INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked. No Parameters Interface NodeFilter (introduced in DOM Level 2) Filters are objects that know how to "filter out" nodes. If a NodeIterator or TreeWalker is given a NodeFilter, it applies the filter before it returns the next node. If the filter says to accept the node, the traversal logic returns it; otherwise, traversal looks for the next node and pretends that the node that was rejected was not there. The DOM does not provide any filters. NodeFilter is just an interface that users can implement to provide their own filters. NodeFilters do not need to know how to traverse from node to node, nor do they need to know anything about the data structure that is being traversed. This makes it very easy to write filters, since the only thing they have to know how to do is evaluate a single node. One filter may be used with a number of different kinds of traversals, encouraging code reuse. IDL Definition // Introduced in DOM Level 2: interface NodeFilter { // Constants returned by acceptNode const short FILTER_ACCEPT = 1; const short FILTER_REJECT = 2; const short FILTER_SKIP = 3; // Constants for whatToShow const unsigned long SHOW_ALL = 0xFFFFFFFF; const unsigned long SHOW_ELEMENT = 0x00000001; const unsigned long SHOW_ATTRIBUTE = 0x00000002; const unsigned long SHOW_TEXT = 0x00000004; const unsigned long SHOW_CDATA_SECTION = 0x00000008; const unsigned long SHOW_ENTITY_REFERENCE = 0x00000010; const unsigned long SHOW_ENTITY = 0x00000020; const unsigned long SHOW_PROCESSING_INSTRUCTION = 0x00000040; const unsigned long SHOW_COMMENT = 0x00000080; const unsigned long SHOW_DOCUMENT = 0x00000100; const unsigned long SHOW_DOCUMENT_TYPE = 0x00000200; const unsigned long SHOW_DOCUMENT_FRAGMENT = 0x00000400; const unsigned long SHOW_NOTATION = 0x00000800; short acceptNode(in Node n); }; Definition group Constants returned by acceptNode The following constants are returned by the acceptNode() method: Defined Constants FILTER_ACCEPT Accept the node. Navigation methods defined for NodeIterator or TreeWalker will return this node. FILTER_REJECT Reject the node. Navigation methods defined for NodeIterator or TreeWalker will not return this node. For TreeWalker, the children of this node will also be rejected. NodeIterators treat this as a synonym for FILTER_SKIP. FILTER_SKIP Skip this single node. Navigation methods defined for NodeIterator or TreeWalker will not return this node. For both NodeIterator and TreeWalker, the children of this node will still be considered. Definition group Constants for whatToShow These are the available values for the whatToShow parameter used in TreeWalkers and NodeIterators. They are the same as the set of possible types for Node, and their values are derived by using a bit position corresponding to the value of nodeType for the equivalent node type. If a bit in whatToShow is set false, that will be taken as a request to skip over this type of node; the behavior in that case is similar to that of FILTER_SKIP. Note that if node types greater than 32 are ever introduced, they may not be individually testable via whatToShow. If that need should arise, it can be handled by selecting SHOW_ALL together with an appropriate NodeFilter. Defined Constants SHOW_ALL Show all Nodes. SHOW_ATTRIBUTE Show Attr nodes. This is meaningful only when creating an iterator or tree-walker with an attribute node as its root; in this case, it means that the attribute node will appear in the first position of the iteration or traversal. Since attributes are never children of other nodes, they do not appear when traversing over the document tree. SHOW_CDATA_SECTION Show CDATASection nodes. SHOW_COMMENT Show Comment nodes. SHOW_DOCUMENT Show Document nodes. SHOW_DOCUMENT_FRAGMENT Show DocumentFragment nodes. SHOW_DOCUMENT_TYPE Show DocumentType nodes. SHOW_ELEMENT Show Element nodes. SHOW_ENTITY Show Entity nodes. This is meaningful only when creating an iterator or tree-walker with an Entity node as its root; in this case, it means that the Entity node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree. SHOW_ENTITY_REFERENCE Show EntityReference nodes. SHOW_NOTATION Show Notation nodes. This is meaningful only when creating an iterator or tree-walker with a Notation node as its root; in this case, it means that the Notation node will appear in the first position of the traversal. Since notations are not part of the document tree, they do not appear when traversing over the document tree. SHOW_PROCESSING_INSTRUCTION Show ProcessingInstruction nodes. SHOW_TEXT Show Text nodes. Methods acceptNode Test whether a specified node is visible in the logical view of a TreeWalker or NodeIterator. This function will be called by the implementation of TreeWalker and NodeIterator; it is not normally called directly from user code. (Though you could do so if you wanted to use the same filter to guide your own application logic.) Parameters n of type Node The node to check to see if it passes the filter or not. Return Value short a constant to determine whether the node is accepted, rejected, or skipped, as defined above. No Exceptions Interface TreeWalker (introduced in DOM Level 2) TreeWalker objects are used to navigate a document tree or subtree using the view of the document defined by their whatToShow flags and filter (if any). Any function which performs navigation using a TreeWalker will automatically support any view defined by a TreeWalker. Omitting nodes from the logical view of a subtree can result in a structure that is substantially different from the same subtree in the complete, unfiltered document. Nodes that are siblings in the TreeWalker view may be children of different, widely separated nodes in the original view. For instance, consider a NodeFilter that skips all nodes except for Text nodes and the root node of a document. In the logical view that results, all text nodes will be siblings and appear as direct children of the root node, no matter how deeply nested the structure of the original document. IDL Definition // Introduced in DOM Level 2: interface TreeWalker { readonly attribute Node root; readonly attribute unsigned long whatToShow; readonly attribute NodeFilter filter; readonly attribute boolean expandEntityReferences; attribute Node currentNode; // raises(DOMException) on setting Node parentNode(); Node firstChild(); Node lastChild(); Node previousSibling(); Node nextSibling(); Node previousNode(); Node nextNode(); }; Attributes currentNode of type Node The node at which the TreeWalker is currently positioned. Alterations to the DOM tree may cause the current node to no longer be accepted by the TreeWalker's associated filter. currentNode may also be explicitly set to any node, whether or not it is within the subtree specified by the root node or would be accepted by the filter and whatToShow flags. Further traversal occurs relative to currentNode even if it is not part of the current view, by applying the filters in the requested direction; if no traversal is possible, currentNode is not changed. Exceptions on setting DOMException NOT_SUPPORTED_ERR: Raised if an attempt is made to set currentNode to null. expandEntityReferences of type boolean, readonly The value of this flag determines whether the children of entity reference nodes are visible to the TreeWalker. If false, they and their descendants will be rejected. Note that this rejection takes precedence over whatToShow and the filter, if any. To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the TreeWalker. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false. filter of type NodeFilter, readonly The filter used to screen nodes. root of type Node, readonly The root node of the TreeWalker, as specified when it was created. whatToShow of type unsigned long, readonly This attribute determines which node types are presented via the TreeWalker. The available set of constants is defined in the NodeFilter interface. Nodes not accepted by whatToShow will be skipped, but their children may still be considered. Note that this skip takes precedence over the filter, if any. Methods firstChild Moves the TreeWalker to the first visible child of the current node, and returns the new node. If the current node has no visible children, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no visible children in the TreeWalker's logical view. No Parameters No Exceptions lastChild Moves the TreeWalker to the last visible child of the current node, and returns the new node. If the current node has no visible children, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no children in the TreeWalker's logical view. No Parameters No Exceptions nextNode Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no next node in the TreeWalker's logical view. No Parameters No Exceptions nextSibling Moves the TreeWalker to the next sibling of the current node, and returns the new node. If the current node has no visible next sibling, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no next sibling. in the TreeWalker's logical view. No Parameters No Exceptions parentNode Moves to and returns the closest visible ancestor node of the current node. If the search for parentNode attempts to step upward from the TreeWalker's root node, or if it fails to find a visible ancestor node, this method retains the current position and returns null. Return Value Node The new parent node, or null if the current node has no parent in the TreeWalker's logical view. No Parameters No Exceptions previousNode Moves the TreeWalker to the previous visible node in document order relative to the current node, and returns the new node. If the current node has no previous node, or if the search for previousNode attempts to step upward from the TreeWalker's root node, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no previous node in the TreeWalker's logical view. No Parameters No Exceptions previousSibling Moves the TreeWalker to the previous sibling of the current node, and returns the new node. If the current node has no visible previous sibling, returns null, and retains the current node. Return Value Node The new node, or null if the current node has no previous sibling. in the TreeWalker's logical view. No Parameters No Exceptions Interface DocumentTraversal (introduced in DOM Level 2) DocumentTraversal contains methods that create iterators and tree-walkers to traverse a node and its children in document order (depth first, pre-order traversal, which is equivalent to the order in which the start tags occur in the text representation of the document). In DOMs which support the Traversal feature, DocumentTraversal will be implemented by the same objects that implement the Document interface. IDL Definition // Introduced in DOM Level 2: interface DocumentTraversal { NodeIterator createNodeIterator(in Node root, in unsigned long whatToShow, in NodeFilter filter, in boolean entityReferenceExpansion) raises(DOMException); TreeWalker createTreeWalker(in Node root, in unsigned long whatToShow, in NodeFilter filter, in boolean entityReferenceExpansion) raises(DOMException); }; Methods createNodeIterator Create a new NodeIterator over the subtree rooted at the specified node. Parameters root of type Node The node which will be iterated together with its children. The iterator is initially positioned just before this node. The whatToShow flags and the filter, if any, are not considered when setting this position. The root must not be null. whatToShow of type unsigned long This flag specifies which node types may appear in the logical view of the tree presented by the iterator. See the description of NodeFilter for the set of possible SHOW_ values. These flags can be combined using OR. filter of type NodeFilter The NodeFilter to be used with this TreeWalker, or null to indicate no filter. entityReferenceExpansion of type boolean The value of this flag determines whether entity reference nodes are expanded. Return Value NodeIterator The newly created NodeIterator. Exceptions DOMException NOT_SUPPORTED_ERR: Raised if the specified root is null. createTreeWalker Create a new TreeWalker over the subtree rooted at the specified node. Parameters root of type Node The node which will serve as the root for the TreeWalker. The whatToShow flags and the NodeFilter are not considered when setting this value; any node type will be accepted as the root. The currentNode of the TreeWalker is initialized to this node, whether or not it is visible. The root functions as a stopping point for traversal methods that look upward in the document structure, such as parentNode and nextNode. The root must not be null. whatToShow of type unsigned long This flag specifies which node types may appear in the logical view of the tree presented by the tree-walker. See the description of NodeFilter for the set of possible SHOW_ values. These flags can be combined using OR. filter of type NodeFilter The NodeFilter to be used with this TreeWalker, or null to indicate no filter. entityReferenceExpansion of type boolean If this flag is false, the contents of EntityReference nodes are not presented in the logical view. Return Value TreeWalker The newly created TreeWalker. Exceptions DOMException NOT_SUPPORTED_ERR: Raised if the specified root is null. 13 November, 2000 2. Document Object Model Range Editors Peter Sharpe, SoftQuad Software Inc. Vidur Apparao, Netscape Communications Corp. Lauren Wood, SoftQuad Software Inc. Table of contents * 2.1. Introduction * 2.2. Definitions and Notation o 2.2.1. Position o 2.2.2. Selection and Partial Selection o 2.2.3. Notation * 2.3. Creating a Range * 2.4. Changing a Range's Position * 2.5. Comparing Range Boundary-Points * 2.6. Deleting Content with a Range * 2.7. Extracting Content * 2.8. Cloning Content * 2.9. Inserting Content * 2.10. Surrounding Content * 2.11. Miscellaneous Members * 2.12. Range modification under document mutation o 2.12.1. Insertions o 2.12.2. Deletions * 2.13. Formal Description of the Range Interface o Range, DocumentRange, RangeException, RangeExceptionCode 2.1. Introduction A Range identifies a range of content in a Document, DocumentFragment or Attr. It is contiguous in the sense that it can be characterized as selecting all of the content between a pair of boundary-points. Note: In a text editor or a word processor, a user can make a selection by pressing down the mouse at one point in a document, moving the mouse to another point, and releasing the mouse. The resulting selection is contiguous and consists of the content between the two points. The term 'selecting' does not mean that every Range corresponds to a selection made by a GUI user; however, such a selection can be returned to a DOM user as a Range. Note: In bidirectional writing (Arabic, Hebrew), a range may correspond to a logical selection that is not necessarily contiguous when displayed. A visually contiguous selection, also used in some cases, may not correspond to a single logical selection, and may therefore have to be represented by more than one range. The Range interface provides methods for accessing and manipulating the document tree at a higher level than similar methods in the Node interface. The expectation is that each of the methods provided by the Range interface for the insertion, deletion and copying of content can be directly mapped to a series of Node editing operations enabled by DOM Core. In this sense, the Range operations can be viewed as convenience methods that also enable the implementation to optimize common editing patterns. This chapter describes the Range interface, including methods for creating and moving a Range and methods for manipulating content with Ranges. The interfaces found within this section are not mandatory. A DOM application may use the hasFeature(feature, version) method of the DOMImplementation interface with parameter values "Range" and "2.0" (respectively) to determine whether or not this module is supported by the implementation. In order to fully support this module, an implementation must also support the "Core" feature defined defined in the DOM Level 2 Core specification [DOM Level 2 Core]. Please refer to additional information about conformance in the DOM Level 2 Core specification [DOM Level 2 Core]. 2.2. Definitions and Notation 2.2.1. Position This chapter refers to two different representations of a document: the text or source form that includes the document markup and the tree representation similar to the one described in the introduction section of the DOM Level 2 Core [DOM Level 2 Core]. A Range consists of two boundary-points corresponding to the start and the end of the Range. A boundary-point's position in a Document or DocumentFragment tree can be characterized by a node and an offset. The node is called the container of the boundary-point and of its position. The container and its ancestors are the ancestor containers of the boundary-point and of its position. The offset within the node is called the offset of the boundary-point and its position. If the container is an Attr, Document, DocumentFragment, Element or EntityReference node, the offset is between its child nodes. If the container is a CharacterData, Comment or ProcessingInstruction node, the offset is between the 16-bit units of the UTF-16 encoded string contained by it. The boundary-points of a Range must have a common ancestor container which is either a Document, DocumentFragment or Attr node. That is, the content of a Range must be entirely within the subtree rooted by a single Document, DocumentFragment or Attr Node. This common ancestor container is known as the root container of the Range. The tree rooted by the root container is known as the Range's context tree. The container of a boundary-point of a Range must be an Element, Comment, ProcessingInstruction, EntityReference, CDATASection, Document, DocumentFragment, Attr, or Text node. None of the ancestor containers of the boundary-point of a Range can be a DocumentType, Entity or Notation node. In terms of the text representation of a document, the boundary-points of a Range can only be on token boundaries. That is, the boundary-point of the text range cannot be in the middle of a start- or end-tag of an element or within the name of an entity or character reference. A Range locates a contiguous portion of the content of the structure model. The relationship between locations in a text representation of the document and in the Node tree interface of the DOM is illustrated in the following diagram: --------------------------------------------------------------------- [Range Example] --------------------------------------------------------------------- Range Example --------------------------------------------------------------------- In this diagram, four different Ranges are illustrated. The boundary-points of each Range are labelled with s# (the start of the Range) and e# (the end of the Range), where # is the number of the Range. For Range 2, the start is in the BODY element and is immediately after the H1 element and immediately before the P element, so its position is between the H1 and P children of BODY. The offset of a boundary-point whose container is not a CharacterData node is 0 if it is before the first child, 1 if between the first and second child, and so on. So, for the start of the Range 2, the container is BODY and the offset is 1. The offset of a boundary-point whose container is a CharacterData node is obtained similarly but using 16-bit unit positions instead. For example, the boundary-point labelled s1 of the Range 1 has a Text node (the one containing "Title") as its container and an offset of 2 since it is between the second and third 16-bit unit. Notice that the boundary-points of Ranges 3 and 4 correspond to the same location in the text representation. An important feature of the Range is that a boundary-point of a Range can unambiguously represent every position within the document tree. The containers and offsets of the boundary-points can be obtained through the following read-only Range attributes: readonly attribute Node startContainer; readonly attribute long startOffset; readonly attribute Node endContainer; readonly attribute long endOffset; If the boundary-points of a Range have the same containers and offsets, the Range is said to be a collapsed Range. (This is often referred to as an insertion point in a user agent.) 2.2.2. Selection and Partial Selection A node or 16-bit unit unit is said to be selected by a Range if it is between the two boundary-points of the Range, that is, if the position immediately before the node or 16-bit unit is before the end of the Range and the position immediately after the node or 16-bit unit is after the start of the range. For example, in terms of a text representation of the document, an element would be selected by a Range if its corresponding start-tag was located after the start of the Range and its end-tag was located before the end of the Range. In the examples in the above diagram, the Range 2 selects the P node and the Range 3 selects the text node containing the text "Blah xyz." A node is said to be partially selected by a Range if it is an ancestor container of exactly one boundary-point of the Range. For example, consider Range 1 in the above diagram. The element H1 is partially selected by that Range since the start of the Range is within one of its children. 2.2.3. Notation Many of the examples in this chapter are illustrated using a text representation of a document. The boundary-points of a Range are indicated by displaying the characters (be they markup or data characters) between the two boundary-points in bold, as in ABCDEF When both boundary-points are at the same position, they are indicated with a bold caret ('^'), as in A^BCDEF 2.3. Creating a Range A Range is created by calling the createRange() method on the DocumentRange interface. This interface can be obtained from the object implementing the Document interface using binding-specific casting methods. interface DocumentRange { Range createRange(); } The initial state of the Range returned from this method is such that both of its boundary-points are positioned at the beginning of the corresponding Document, before any content. In other words, the container of each boundary-point is the Document node and the offset within that node is 0. Like some objects created using methods in the Document interface (such as Nodes and DocumentFragments), Ranges created via a particular document instance can select only content associated with that Document, or with DocumentFragments and Attrs for which that Document is the ownerDocument. Such Ranges, then, can not be used with other Document instances. 2.4. Changing a Range's Position A Range's position can be specified by setting the container and offset of each boundary-point with the setStart and setEnd methods. void setStart(in Node parent, in long offset) raises(RangeException); void setEnd(in Node parent, in long offset) raises(RangeException); If one boundary-point of a Range is set to have a root container other than the current one for the Range, the Range is collapsed to the new position. This enforces the restriction that both boundary-points of a Range must have the same root container. The start position of a Range is guaranteed to never be after the end position. To enforce this restriction, if the start is set to be at a position after the end, the Range is collapsed to that position. Similarly, if the end is set to be at a position before the start, the Range is collapsed to that position. It is also possible to set a Range's position relative to nodes in the tree: void setStartBefore(in Node node); raises(RangeException); void setStartAfter(in Node node); raises(RangeException); void setEndBefore(in Node node); raises(RangeException); void setEndAfter(in Node node); raises(RangeException); The parent of the node becomes the container of the boundary-point and the Range is subject to the same restrictions as given above in the description of setStart()and setEnd(). A Range can be collapsed to either boundary-point: void collapse(in boolean toStart); Passing TRUE as the parameter toStart will collapse the Range to its start, FALSE to its end. Testing whether a Range is collapsed can be done by examining the collapsed attribute: readonly attribute boolean collapsed; The following methods can be used to make a Range select the contents of a node or the node itself. void selectNode(in Node n); void selectNodeContents(in Node n); The following examples demonstrate the operation of the methods selectNode and selectNodeContents: Before: ^ABC After Range.selectNodeContents(FOO): ABC (In this case, FOO is the parent of both boundary-points) After Range.selectNode(FOO): ABC 2.5. Comparing Range Boundary-Points It is possible to compare two Ranges by comparing their boundary-points: short compareBoundaryPoints(in CompareHow how, in Range sourceRange) raises(RangeException); where CompareHow is one of four values: START_TO_START, START_TO_END, END_TO_END and END_TO_START. The return value is -1, 0 or 1 depending on whether the corresponding boundary-point of the Range is before, equal to, or after the corresponding boundary-point of sourceRange. An exception is thrown if the two Ranges have different root containers. The result of comparing two boundary-points (or positions) is specified below. An informal but not always correct specification is that an boundary-point is before, equal to, or after another if it corresponds to a location in a text representation before, equal to, or after the other's corresponding location. Let A and B be two boundary-points or positions. Then one of the following holds: A is before B, A is equal to B, or A is after B. Which one holds is specified in the following by examining four cases: In the first case the boundary-points have the same container. A is before B if its offset is less than the offset of B, A is equal to B if its offset is equal to the offset of B, and A is after B if its offset is greater than the offset of B. In the second case a child node C of the container of A is an ancestor container of B. In this case, A is before B if the offset of A is less than or equal to the index of the child node C and A is after B otherwise. In the third case a child node C of the container of B is an ancestor container of A. In this case, A is before B if the index of the child node C is less than the offset of B and A is after B otherwise. In the fourth case, none of three other cases hold: the containers of A and B are siblings or descendants of sibling nodes. In this case, A is before B if the container of A is before the container of B in a pre-order traversal of the Ranges' context tree and A is after B otherwise. Note that because the same location in a text representation of the document can correspond to two different positions in the DOM tree, it is possible for two boundary-points to not compare equal even though they would be equal in the text representation. For this reason, the informal definition above can sometimes be incorrect. 2.6. Deleting Content with a Range One can delete the contents selected by a Range with: void deleteContents(); deleteContents() deletes all nodes and characters selected by the Range. All other nodes and characters remain in the context tree of the Range. Some examples of this deletion operation are: (1) ABCDCD --> A^CD (2) ABCDE --> AB^E (3) XYZWQ --> X^WQ (4) ABCD --> A^D After deleteContents() is invoked on a Range, the Range is collapsed. If no node was partially selected by the Range, then it is collapsed to its original start point, as in example (1). If a node was partially selected by the Range and was an ancestor container of the start of the Range and no ancestor of the node satisfies these two conditions, then the Range is collapsed to the position immediately after the node, as in examples (2) and (4). If a node was partially selected by the Range and was an ancestor container of the end of the Range and no ancestor of the node satisfies these two conditions, then the Range is collapsed to the position immediately before the node, as in examples (3) and (4). Note that if deletion of a Range leaves adjacent Text nodes, they are not automatically merged, and empty Text nodes are not automatically removed. Two Text nodes should be joined only if each is the container of one of the boundary-points of a Range whose contents are deleted. To merge adjacent Text nodes, or remove empty text nodes, the normalize() method on the Node interface should be used. 2.7. Extracting Content If the contents of a Range need to be extracted rather than deleted, the following method may be used: DocumentFragment extractContents(); The extractContents() method removes nodes from the Range's context tree similarly to the deleteContents() method. In addition, it places the deleted contents in a new DocumentFragment. The following examples illustrate the contents of the returned DocumentFragment: (1) ABCDCD --> BCD (2) ABCDE --> CD (3) XYZWQ --> YZ (4) ABCD --> BC It is important to note that nodes that are partially selected by the Range are cloned. Since part of such a node's contents must remain in the Range's context tree and part of the contents must be moved to the new DocumentFragment, a clone of the partially selected node is included in the new DocumentFragment. Note that cloning does not take place for selected elements; these nodes are moved to the new DocumentFragment. 2.8. Cloning Content The contents of a Range may be duplicated using the following method: DocumentFragment cloneContents(); This method returns a DocumentFragment that is similar to the one returned by the method extractContents(). However, in this case, the original nodes and character data in the Range are not removed from the Range's context tree. Instead, all of the nodes and text content within the returned DocumentFragment are cloned. 2.9. Inserting Content A node may be inserted into a Range using the following method: void insertNode(in Node n) raises(RangeException); The insertNode() method inserts the specified node into the Range's context tree. The node is inserted at the start boundary-point of the Range, without modifying it. If the start boundary point of the Range is in a Text node, the insertNode operation splits the Text node at the boundary point. If the node to be inserted is also a Text node, the resulting adjacent Text nodes are not normalized automatically; this operation is left to the application. The Node passed into this method can be a DocumentFragment. In that case, the contents of the DocumentFragment are inserted at the start boundary-point of the Range, but the DocumentFragment itself is not. Note that if the Node represents the root of a sub-tree, the entire sub-tree is inserted. The same rules that apply to the insertBefore() method on the Node interface apply here. Specifically, the Node passed in, if it already has a parent, will be removed from its existing position. 2.10. Surrounding Content The insertion of a single node to subsume the content selected by a Range can be performed with: void surroundContents(in Node newParent); The surroundContents() method causes all of the content selected by the Range to be rooted by the specified node. The nodes may not be Attr, Entity, DocumentType, Notation, Document, or DocumentFragment nodes. Calling surroundContents() with the Element node FOO in the following examples yields: Before: ABCDE After surroundContents(FOO): ABCDE Another way of describing the effect of this method on the Range's context tree is to decompose it in terms of other operations: 1. Remove the contents selected by the Range with a call to extractContents(). 2. Insert the node newParent where the Range is collapsed (after the extraction) with insertNode(). 3. Insert the entire contents of the extracted DocumentFragment into newParent. Specifically, invoke the appendChild() on newParent passing in the DocumentFragment returned as a result of the call to extractContents() 4. Select newParent and all of its contents with selectNode(). The surroundContents() method raises an exception if the Range partially selects a non-Text node. An example of a Range for which surroundContents()raises an exception is: ABCDE If the node newParent has any children, those children are removed before its insertion. Also, if the node newParent already has a parent, it is removed from the original parent's childNodes list. 2.11. Miscellaneous Members One can clone a Range: Range cloneRange(); This creates a new Range which selects exactly the same content as that selected by the Range on which the method cloneRange was invoked. No content is affected by this operation. Because the boundary-points of a Range do not necessarily have the same containers, use: readonly attribute Node commonAncestorContainer; to get the ancestor container of both boundary-points that is furthest down from the Range's root container One can get a copy of all the character data selected or partially selected by a Range with: DOMString toString(); This does nothing more than simply concatenate all the character data selected by the Range. This includes character data in both Text and CDATASection nodes. 2.12. Range modification under document mutation As a document is modified, the Ranges within the document need to be updated. For example, if one boundary-point of a Range is within a node and that node is removed from the document, then the Range would be invalid unless it is fixed up in some way. This section describes how Ranges are modified under document mutations so that they remain valid. There are two general principles which apply to Ranges under document mutation: The first is that all Ranges in a document will remain valid after any mutation operation and the second is that, as much as possible, all Ranges will select the same portion of the document after any mutation operation. Any mutation of the document tree which affect Ranges can be considered to be a combination of basic deletion and insertion operations. In fact, it can be convenient to think of those operations as being accomplished using the deleteContents() and insertNode() Range methods and, in the case of Text mutations, the splitText() and normalize() methods. 2.12.1. Insertions An insertion occurs at a single point, the insertion point, in the document. For any Range in the document tree, consider each boundary-point. The only case in which the boundary-point will be changed after the insertion is when the boundary-point and the insertion point have the same container and the offset of the insertion point is strictly less than the offset of the Range's boundary-point. In that case the offset of the Range's boundary-point will be increased so that it is between the same nodes or characters as it was before the insertion. Note that when content is inserted at a boundary-point, it is ambiguous as to where the boundary-point should be repositioned if its relative position is to be maintained. There are two possibilities: at the start or at the end of the newly inserted content. We have chosen that in this case neither the container nor offset of the boundary-point is changed. As a result, the boundary-point will be positioned at the start of the newly inserted content. Examples: Suppose the Range selects the following:

Abcd efgh XY blah ijkl

Consider the insertion of the text "inserted text" at the following positions: 1. Before the 'X':

Abcd efgh inserted textXY blah ijkl

2. After the 'X':

Abcd efgh Xinserted textY blah ijkl

3. After the 'Y':

Abcd efgh XYinserted text blah ijkl

4. After the 'h' in "Y blah":

Abcd efgh XY blahinserted text ijkl

2.12.2. Deletions Any deletion from the document tree can be considered as a sequence of deleteContents() operations applied to a minimal set of disjoint Ranges. To specify how a Range is modified under deletions we need only consider what happens to a Range under a single deleteContents()operation of another Range. And, in fact, we need only consider what happens to a single boundary-point of the Range since both boundary-points are modified using the same algorithm. If a boundary-point of the original Range is within the content being deleted, then after the deletion it will be at the same position as the resulting boundary-point of the (now collapsed) Range used to delete the contents. If a boundary-point is after the content being deleted then it is not affected by the deletion unless its container is also the container of one of the boundary-points of the Range being deleted. If there is such a common container, then the index of the boundary-point is modified so that the boundary-point maintains its position relative to the content of the container. If a boundary-point is before the content being deleted then it is not affected by the deletion at all. Examples: In these examples, the Range on which deleteContents()is invoked is indicated by the underline. Example 1. Before:

Abcd efgh The Range ijkl

After:

Abcd Range ijkl

Example 2. Before:

Abcd efgh The Range ijkl

After:

Abcd ^kl

Example 3. Before:

ABCD efgh The Range ijkl

After:

ABCD ange ijkl

In this example, the container of the start boundary-point after the deletion is the Text node holding the string "ange". Example 4. Before:

Abcd efgh The Range ijkl

After:

Abcd he Range ijkl

Example 5. Before:

Abcd efgh The Range ijkl

After:

Abcd ^kl

2.13. Formal Description of the Range Interface To summarize, the complete, formal description of the Range interface is given below: Interface Range (introduced in DOM Level 2) IDL Definition // Introduced in DOM Level 2: interface Range { readonly attribute Node startContainer; // raises(DOMException) on retrieval readonly attribute long startOffset; // raises(DOMException) on retrieval readonly attribute Node endContainer; // raises(DOMException) on retrieval readonly attribute long endOffset; // raises(DOMException) on retrieval readonly attribute boolean collapsed; // raises(DOMException) on retrieval readonly attribute Node commonAncestorContainer; // raises(DOMException) on retrieval void setStart(in Node refNode, in long offset) raises(RangeException, DOMException); void setEnd(in Node refNode, in long offset) raises(RangeException, DOMException); void setStartBefore(in Node refNode) raises(RangeException, DOMException); void setStartAfter(in Node refNode) raises(RangeException, DOMException); void setEndBefore(in Node refNode) raises(RangeException, DOMException); void setEndAfter(in Node refNode) raises(RangeException, DOMException); void collapse(in boolean toStart) raises(DOMException); void selectNode(in Node refNode) raises(RangeException, DOMException); void selectNodeContents(in Node refNode) raises(RangeException, DOMException); // CompareHow const unsigned short START_TO_START = 0; const unsigned short START_TO_END = 1; const unsigned short END_TO_END = 2; const unsigned short END_TO_START = 3; short compareBoundaryPoints(in unsigned short how, in Range sourceRange) raises(DOMException); void deleteContents() raises(DOMException); DocumentFragment extractContents() raises(DOMException); DocumentFragment cloneContents() raises(DOMException); void insertNode(in Node newNode) raises(DOMException, RangeException); void surroundContents(in Node newParent) raises(DOMException, RangeException); Range cloneRange() raises(DOMException); DOMString toString() raises(DOMException); void detach() raises(DOMException); }; Definition group CompareHow Passed as a parameter to the compareBoundaryPoints method. Defined Constants END_TO_END Compare end boundary-point of sourceRange to end boundary-point of Range on which compareBoundaryPoints is invoked. END_TO_START Compare end boundary-point of sourceRange to start boundary-point of Range on which compareBoundaryPoints is invoked. START_TO_END Compare start boundary-point of sourceRange to end boundary-point of Range on which compareBoundaryPoints is invoked. START_TO_START Compare start boundary-point of sourceRange to start boundary-point of Range on which compareBoundaryPoints is invoked. Attributes collapsed of type boolean, readonly TRUE if the Range is collapsed Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. commonAncestorContainer of type Node, readonly The deepest common ancestor container of the Range's two boundary-points. Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. endContainer of type Node, readonly Node within which the Range ends Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. endOffset of type long, readonly Offset within the ending node of the Range. Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. startContainer of type Node, readonly Node within which the Range begins Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. startOffset of type long, readonly Offset within the starting node of the Range. Exceptions on retrieval DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. Methods cloneContents Duplicates the contents of a Range Return Value DocumentFragment A DocumentFragment that contains content equivalent to this Range. Exceptions DOMException HIERARCHY_REQUEST_ERR: Raised if a DocumentType node would be extracted into the new DocumentFragment. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters cloneRange Produces a new Range whose boundary-points are equal to the boundary-points of the Range. Return Value Range The duplicated Range. Exceptions DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters collapse Collapse a Range onto one of its boundary-points Parameters toStart of type boolean If TRUE, collapses the Range onto its start; if FALSE, collapses it onto its end. Exceptions DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value compareBoundaryPoints Compare the boundary-points of two Ranges in a document. Parameters how of type unsigned short A code representing the type of comparison, as defined above. sourceRange of type Range The Range on which this current Range is compared to. Return Value short -1, 0 or 1 depending on whether the corresponding boundary-point of the Range is respectively before, equal to, or after the corresponding boundary-point of sourceRange. Exceptions DOMException WRONG_DOCUMENT_ERR: Raised if the two Ranges are not in the same Document or DocumentFragment. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. deleteContents Removes the contents of a Range from the containing document or document fragment without returning a reference to the removed content. Exceptions DOMException NO_MODIFICATION_ALLOWED_ERR: Raised if any portion of the content of the Range is read-only or any of the nodes that contain any of the content of the Range are read-only. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters No Return Value detach Called to indicate that the Range is no longer in use and that the implementation may relinquish any resources associated with this Range. Subsequent calls to any methods or attribute getters on this Range will result in a DOMException being thrown with an error code of INVALID_STATE_ERR. Exceptions DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters No Return Value extractContents Moves the contents of a Range from the containing document or document fragment to a new DocumentFragment. Return Value DocumentFragment A DocumentFragment containing the extracted contents. Exceptions DOMException NO_MODIFICATION_ALLOWED_ERR: Raised if any portion of the content of the Range is read-only or any of the nodes which contain any of the content of the Range are read-only. HIERARCHY_REQUEST_ERR: Raised if a DocumentType node would be extracted into the new DocumentFragment. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters insertNode Inserts a node into the Document or DocumentFragment at the start of the Range. If the container is a Text node, this will be split at the start of the Range (as if the Text node's splitText method was performed at the insertion point) and the insertion will occur between the two resulting Text nodes. Adjacent Text nodes will not be automatically merged. If the node to be inserted is a DocumentFragment node, the children will be inserted rather than the DocumentFragment node itself. Parameters newNode of type Node The node to insert at the start of the Range Exceptions DOMException NO_MODIFICATION_ALLOWED_ERR: Raised if an ancestor container of the start of the Range is read-only. WRONG_DOCUMENT_ERR: Raised if newNode and the container of the start of the Range were not created from the same document. HIERARCHY_REQUEST_ERR: Raised if the container of the start of the Range is of a type that does not allow children of the type of newNode or if newNode is an ancestor of the container. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. RangeException INVALID_NODE_TYPE_ERR: Raised if newNode is an Attr, Entity, Notation, or Document node. No Return Value selectNode Select a node and its contents Parameters refNode of type Node The node to select. Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if an ancestor of refNode is an Entity, Notation or DocumentType node or if refNode is a Document, DocumentFragment, Attr, Entity, or Notation node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value selectNodeContents Select the contents within a node Parameters refNode of type Node Node to select from Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if refNode or an ancestor of refNode is an Entity, Notation or DocumentType node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setEnd Sets the attributes describing the end of a Range. Parameters refNode of type Node The refNode value. This parameter must be different from null. offset of type long The endOffset value. Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if refNode or an ancestor of refNode is an Entity, Notation, or DocumentType node. DOMException INDEX_SIZE_ERR: Raised if offset is negative or greater than the number of child units in refNode. Child units are 16-bit units if refNode is a type of CharacterData node (e.g., a Text or Comment node) or a ProcessingInstruction node. Child units are Nodes in all other cases. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setEndAfter Sets the end of a Range to be after a node Parameters refNode of type Node Range ends after refNode. Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if the root container of refNode is not an Attr, Document or DocumentFragment node or if refNode is a Document, DocumentFragment, Attr, Entity, or Notation node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setEndBefore Sets the end position to be before a node. Parameters refNode of type Node Range ends before refNode Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if the root container of refNode is not an Attr, Document, or DocumentFragment node or if refNode is a Document, DocumentFragment, Attr, Entity, or Notation node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setStart Sets the attributes describing the start of the Range. Parameters refNode of type Node The refNode value. This parameter must be different from null. offset of type long The startOffset value. Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if refNode or an ancestor of refNode is an Entity, Notation, or DocumentType node. DOMException INDEX_SIZE_ERR: Raised if offset is negative or greater than the number of child units in refNode. Child units are 16-bit units if refNode is a type of CharacterData node (e.g., a Text or Comment node) or a ProcessingInstruction node. Child units are Nodes in all other cases. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setStartAfter Sets the start position to be after a node Parameters refNode of type Node Range starts after refNode Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if the root container of refNode is not an Attr, Document, or DocumentFragment node or if refNode is a Document, DocumentFragment, Attr, Entity, or Notation node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value setStartBefore Sets the start position to be before a node Parameters refNode of type Node Range starts before refNode Exceptions RangeException INVALID_NODE_TYPE_ERR: Raised if the root container of refNode is not an Attr, Document, or DocumentFragment node or if refNode is a Document, DocumentFragment, Attr, Entity, or Notation node. DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Return Value surroundContents Reparents the contents of the Range to the given node and inserts the node at the position of the start of the Range. Parameters newParent of type Node The node to surround the contents with. Exceptions DOMException NO_MODIFICATION_ALLOWED_ERR: Raised if an ancestor container of either boundary-point of the Range is read-only. WRONG_DOCUMENT_ERR: Raised if newParent and the container of the start of the Range were not created from the same document. HIERARCHY_REQUEST_ERR: Raised if the container of the start of the Range is of a type that does not allow children of the type of newParent or if newParent is an ancestor of the container or if node would end up with a child node of a type not allowed by the type of node. INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. RangeException BAD_BOUNDARYPOINTS_ERR: Raised if the Range partially selects a non-text node. INVALID_NODE_TYPE_ERR: Raised if node is an Attr, Entity, DocumentType, Notation, Document, or DocumentFragment node. No Return Value toString Returns the contents of a Range as a string. This string contains only the data characters, not any markup. Return Value DOMString The contents of the Range. Exceptions DOMException INVALID_STATE_ERR: Raised if detach() has already been invoked on this object. No Parameters Interface DocumentRange (introduced in DOM Level 2) IDL Definition // Introduced in DOM Level 2: interface DocumentRange { Range createRange(); }; Methods createRange This interface can be obtained from the object implementing the Document interface using binding-specific casting methods. Return Value Range The initial state of the Range returned from this method is such that both of its boundary-points are positioned at the beginning of the corresponding Document, before any content. The Range returned can only be used to select content associated with this Document, or with DocumentFragments and Attrs for which this Document is the ownerDocument. No Parameters No Exceptions Exception RangeException introduced in DOM Level 2 Range operations may throw a RangeException as specified in their method descriptions. IDL Definition // Introduced in DOM Level 2: exception RangeException { unsigned short code; }; // RangeExceptionCode const unsigned short BAD_BOUNDARYPOINTS_ERR = 1; const unsigned short INVALID_NODE_TYPE_ERR = 2; Definition group RangeExceptionCode An integer indicating the type of error generated. Defined Constants BAD_BOUNDARYPOINTS_ERR If the boundary-points of a Range do not meet specific requirements. INVALID_NODE_TYPE_ERR If the container of an boundary-point of a Range is being set to either a node of an invalid type or a node with an ancestor of an invalid type. 13 November, 2000 Appendix A: IDL Definitions This appendix contains the complete OMG IDL [OMGIDL] for the Level 2 Document Object Model Traversal and Range definitions. The definitions are divided into Traversal, and Range. The IDL files are also available as: http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/idl.zip A.1: Document Object Model Traversal traversal.idl: // File: traversal.idl #ifndef _TRAVERSAL_IDL_ #define _TRAVERSAL_IDL_ #include "dom.idl" #pragma prefix "dom.w3c.org" module traversal { typedef dom::Node Node; interface NodeFilter; // Introduced in DOM Level 2: interface NodeIterator { readonly attribute Node root; readonly attribute unsigned long whatToShow; readonly attribute NodeFilter filter; readonly attribute boolean expandEntityReferences; Node nextNode() raises(dom::DOMException); Node previousNode() raises(dom::DOMException); void detach(); }; // Introduced in DOM Level 2: interface NodeFilter { // Constants returned by acceptNode const short FILTER_ACCEPT = 1; const short FILTER_REJECT = 2; const short FILTER_SKIP = 3; // Constants for whatToShow const unsigned long SHOW_ALL = 0xFFFFFFFF; const unsigned long SHOW_ELEMENT = 0x00000001; const unsigned long SHOW_ATTRIBUTE = 0x00000002; const unsigned long SHOW_TEXT = 0x00000004; const unsigned long SHOW_CDATA_SECTION = 0x00000008; const unsigned long SHOW_ENTITY_REFERENCE = 0x00000010; const unsigned long SHOW_ENTITY = 0x00000020; const unsigned long SHOW_PROCESSING_INSTRUCTION = 0x00000040; const unsigned long SHOW_COMMENT = 0x00000080; const unsigned long SHOW_DOCUMENT = 0x00000100; const unsigned long SHOW_DOCUMENT_TYPE = 0x00000200; const unsigned long SHOW_DOCUMENT_FRAGMENT = 0x00000400; const unsigned long SHOW_NOTATION = 0x00000800; short acceptNode(in Node n); }; // Introduced in DOM Level 2: interface TreeWalker { readonly attribute Node root; readonly attribute unsigned long whatToShow; readonly attribute NodeFilter filter; readonly attribute boolean expandEntityReferences; attribute Node currentNode; // raises(dom::DOMException) on setting Node parentNode(); Node firstChild(); Node lastChild(); Node previousSibling(); Node nextSibling(); Node previousNode(); Node nextNode(); }; // Introduced in DOM Level 2: interface DocumentTraversal { NodeIterator createNodeIterator(in Node root, in unsigned long whatToShow, in NodeFilter filter, in boolean entityReferenceExpansion) raises(dom::DOMException); TreeWalker createTreeWalker(in Node root, in unsigned long whatToShow, in NodeFilter filter, in boolean entityReferenceExpansion) raises(dom::DOMException); }; }; #endif // _TRAVERSAL_IDL_ A.2: Document Object Model Range ranges.idl: // File: ranges.idl #ifndef _RANGES_IDL_ #define _RANGES_IDL_ #include "dom.idl" #pragma prefix "dom.w3c.org" module ranges { typedef dom::Node Node; typedef dom::DocumentFragment DocumentFragment; typedef dom::DOMString DOMString; // Introduced in DOM Level 2: exception RangeException { unsigned short code; }; // RangeExceptionCode const unsigned short BAD_BOUNDARYPOINTS_ERR = 1; const unsigned short INVALID_NODE_TYPE_ERR = 2; // Introduced in DOM Level 2: interface Range { readonly attribute Node startContainer; // raises(dom::DOMException) on retrieval readonly attribute long startOffset; // raises(dom::DOMException) on retrieval readonly attribute Node endContainer; // raises(dom::DOMException) on retrieval readonly attribute long endOffset; // raises(dom::DOMException) on retrieval readonly attribute boolean collapsed; // raises(dom::DOMException) on retrieval readonly attribute Node commonAncestorContainer; // raises(dom::DOMException) on retrieval void setStart(in Node refNode, in long offset) raises(RangeException, dom::DOMException); void setEnd(in Node refNode, in long offset) raises(RangeException, dom::DOMException); void setStartBefore(in Node refNode) raises(RangeException, dom::DOMException); void setStartAfter(in Node refNode) raises(RangeException, dom::DOMException); void setEndBefore(in Node refNode) raises(RangeException, dom::DOMException); void setEndAfter(in Node refNode) raises(RangeException, dom::DOMException); void collapse(in boolean toStart) raises(dom::DOMException); void selectNode(in Node refNode) raises(RangeException, dom::DOMException); void selectNodeContents(in Node refNode) raises(RangeException, dom::DOMException); // CompareHow const unsigned short START_TO_START = 0; const unsigned short START_TO_END = 1; const unsigned short END_TO_END = 2; const unsigned short END_TO_START = 3; short compareBoundaryPoints(in unsigned short how, in Range sourceRange) raises(dom::DOMException); void deleteContents() raises(dom::DOMException); DocumentFragment extractContents() raises(dom::DOMException); DocumentFragment cloneContents() raises(dom::DOMException); void insertNode(in Node newNode) raises(dom::DOMException, RangeException); void surroundContents(in Node newParent) raises(dom::DOMException, RangeException); Range cloneRange() raises(dom::DOMException); DOMString toString() raises(dom::DOMException); void detach() raises(dom::DOMException); }; // Introduced in DOM Level 2: interface DocumentRange { Range createRange(); }; }; #endif // _RANGES_IDL_ 13 November, 2000 Appendix B: Java Language Binding This appendix contains the complete Java Language [Java] binding for the Level 2 Document Object Model Traversal and Range. The definitions are divided into Traversal, and Range. The Java files are also available as http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/java-binding.zip B.1: Document Object Model Traversal org/w3c/dom/traversal/NodeIterator.java: package org.w3c.dom.traversal; import org.w3c.dom.Node; import org.w3c.dom.DOMException; public interface NodeIterator { public Node getRoot(); public int getWhatToShow(); public NodeFilter getFilter(); public boolean getExpandEntityReferences(); public Node nextNode() throws DOMException; public Node previousNode() throws DOMException; public void detach(); } org/w3c/dom/traversal/NodeFilter.java: package org.w3c.dom.traversal; import org.w3c.dom.Node; public interface NodeFilter { // Constants returned by acceptNode public static final short FILTER_ACCEPT = 1; public static final short FILTER_REJECT = 2; public static final short FILTER_SKIP = 3; // Constants for whatToShow public static final int SHOW_ALL = 0xFFFFFFFF; public static final int SHOW_ELEMENT = 0x00000001; public static final int SHOW_ATTRIBUTE = 0x00000002; public static final int SHOW_TEXT = 0x00000004; public static final int SHOW_CDATA_SECTION = 0x00000008; public static final int SHOW_ENTITY_REFERENCE = 0x00000010; public static final int SHOW_ENTITY = 0x00000020; public static final int SHOW_PROCESSING_INSTRUCTION = 0x00000040; public static final int SHOW_COMMENT = 0x00000080; public static final int SHOW_DOCUMENT = 0x00000100; public static final int SHOW_DOCUMENT_TYPE = 0x00000200; public static final int SHOW_DOCUMENT_FRAGMENT = 0x00000400; public static final int SHOW_NOTATION = 0x00000800; public short acceptNode(Node n); } org/w3c/dom/traversal/TreeWalker.java: package org.w3c.dom.traversal; import org.w3c.dom.Node; import org.w3c.dom.DOMException; public interface TreeWalker { public Node getRoot(); public int getWhatToShow(); public NodeFilter getFilter(); public boolean getExpandEntityReferences(); public Node getCurrentNode(); public void setCurrentNode(Node currentNode) throws DOMException; public Node parentNode(); public Node firstChild(); public Node lastChild(); public Node previousSibling(); public Node nextSibling(); public Node previousNode(); public Node nextNode(); } org/w3c/dom/traversal/DocumentTraversal.java: package org.w3c.dom.traversal; import org.w3c.dom.Node; import org.w3c.dom.DOMException; public interface DocumentTraversal { public NodeIterator createNodeIterator(Node root, int whatToShow, NodeFilter filter, boolean entityReferenceExpansion) throws DOMException; public TreeWalker createTreeWalker(Node root, int whatToShow, NodeFilter filter, boolean entityReferenceExpansion) throws DOMException; } B.2: Document Object Model Range org/w3c/dom/ranges/RangeException.java: package org.w3c.dom.ranges; public class RangeException extends RuntimeException { public RangeException(short code, String message) { super(message); this.code = code; } public short code; // RangeExceptionCode public static final short BAD_BOUNDARYPOINTS_ERR = 1; public static final short INVALID_NODE_TYPE_ERR = 2; } org/w3c/dom/ranges/Range.java: package org.w3c.dom.ranges; import org.w3c.dom.Node; import org.w3c.dom.DocumentFragment; import org.w3c.dom.DOMException; public interface Range { public Node getStartContainer() throws DOMException; public int getStartOffset() throws DOMException; public Node getEndContainer() throws DOMException; public int getEndOffset() throws DOMException; public boolean getCollapsed() throws DOMException; public Node getCommonAncestorContainer() throws DOMException; public void setStart(Node refNode, int offset) throws RangeException, DOMException; public void setEnd(Node refNode, int offset) throws RangeException, DOMException; public void setStartBefore(Node refNode) throws RangeException, DOMException; public void setStartAfter(Node refNode) throws RangeException, DOMException; public void setEndBefore(Node refNode) throws RangeException, DOMException; public void setEndAfter(Node refNode) throws RangeException, DOMException; public void collapse(boolean toStart) throws DOMException; public void selectNode(Node refNode) throws RangeException, DOMException; public void selectNodeContents(Node refNode) throws RangeException, DOMException; // CompareHow public static final short START_TO_START = 0; public static final short START_TO_END = 1; public static final short END_TO_END = 2; public static final short END_TO_START = 3; public short compareBoundaryPoints(short how, Range sourceRange) throws DOMException; public void deleteContents() throws DOMException; public DocumentFragment extractContents() throws DOMException; public DocumentFragment cloneContents() throws DOMException; public void insertNode(Node newNode) throws DOMException, RangeException; public void surroundContents(Node newParent) throws DOMException, RangeException; public Range cloneRange() throws DOMException; public String toString() throws DOMException; public void detach() throws DOMException; } org/w3c/dom/ranges/DocumentRange.java: package org.w3c.dom.ranges; public interface DocumentRange { public Range createRange(); } 13 November, 2000 Appendix C: ECMAScript Language Binding This appendix contains the complete ECMAScript [ECMAScript] binding for the Level 2 Document Object Model Traversal and Range definitions. The definitions are divided into Traversal, and Range. Note: Exceptions handling is only supported by ECMAScript implementation conformant with the Standard ECMA-262 3rd. Edition ([ECMAScript]). C.1: Document Object Model Traversal Object NodeIterator The NodeIterator object has the following properties: root This read-only property is a Node object. whatToShow This read-only property is of type Number. filter This read-only property is a NodeFilter object. expandEntityReferences This read-only property is of type Boolean. The NodeIterator object has the following methods: nextNode() This method returns a Node object. This method can raise a DOMException object. previousNode() This method returns a Node object. This method can raise a DOMException object. detach() This method has no return value. Prototype Object NodeFilter The NodeFilter class has the following constants: NodeFilter.FILTER_ACCEPT This constant is of type short and its value is 1. NodeFilter.FILTER_REJECT This constant is of type short and its value is 2. NodeFilter.FILTER_SKIP This constant is of type short and its value is 3. NodeFilter.SHOW_ALL This constant is of type Number and its value is 0xFFFFFFFF. NodeFilter.SHOW_ELEMENT This constant is of type Number and its value is 0x00000001. NodeFilter.SHOW_ATTRIBUTE This constant is of type Number and its value is 0x00000002. NodeFilter.SHOW_TEXT This constant is of type Number and its value is 0x00000004. NodeFilter.SHOW_CDATA_SECTION This constant is of type Number and its value is 0x00000008. NodeFilter.SHOW_ENTITY_REFERENCE This constant is of type Number and its value is 0x00000010. NodeFilter.SHOW_ENTITY This constant is of type Number and its value is 0x00000020. NodeFilter.SHOW_PROCESSING_INSTRUCTION This constant is of type Number and its value is 0x00000040. NodeFilter.SHOW_COMMENT This constant is of type Number and its value is 0x00000080. NodeFilter.SHOW_DOCUMENT This constant is of type Number and its value is 0x00000100. NodeFilter.SHOW_DOCUMENT_TYPE This constant is of type Number and its value is 0x00000200. NodeFilter.SHOW_DOCUMENT_FRAGMENT This constant is of type Number and its value is 0x00000400. NodeFilter.SHOW_NOTATION This constant is of type Number and its value is 0x00000800. Object NodeFilter This is an ECMAScript function reference. This method returns a Number. The parameter is a Node object. Object TreeWalker The TreeWalker object has the following properties: root This read-only property is a Node object. whatToShow This read-only property is of type Number. filter This read-only property is a NodeFilter object. expandEntityReferences This read-only property is of type Boolean. currentNode This property is a Node object and can raise a DOMException object on setting. The TreeWalker object has the following methods: parentNode() This method returns a Node object. firstChild() This method returns a Node object. lastChild() This method returns a Node object. previousSibling() This method returns a Node object. nextSibling() This method returns a Node object. previousNode() This method returns a Node object. nextNode() This method returns a Node object. Object DocumentTraversal The DocumentTraversal object has the following methods: createNodeIterator(root, whatToShow, filter, entityReferenceExpansion) This method returns a NodeIterator object. The root parameter is a Node object. The whatToShow parameter is of type Number. The filter parameter is a NodeFilter object. The entityReferenceExpansion parameter is of type Boolean. This method can raise a DOMException object. createTreeWalker(root, whatToShow, filter, entityReferenceExpansion) This method returns a TreeWalker object. The root parameter is a Node object. The whatToShow parameter is of type Number. The filter parameter is a NodeFilter object. The entityReferenceExpansion parameter is of type Boolean. This method can raise a DOMException object. C.2: Document Object Model Range Prototype Object Range The Range class has the following constants: Range.START_TO_START This constant is of type Number and its value is 0. Range.START_TO_END This constant is of type Number and its value is 1. Range.END_TO_END This constant is of type Number and its value is 2. Range.END_TO_START This constant is of type Number and its value is 3. Object Range The Range object has the following properties: startContainer This read-only property is a Node object and can raise a DOMException object on retrieval. startOffset This read-only property is a long object and can raise a DOMException object on retrieval. endContainer This read-only property is a Node object and can raise a DOMException object on retrieval. endOffset This read-only property is a long object and can raise a DOMException object on retrieval. collapsed This read-only property is of type Boolean and can raise a DOMException object on retrieval. commonAncestorContainer This read-only property is a Node object and can raise a DOMException object on retrieval. The Range object has the following methods: setStart(refNode, offset) This method has no return value. The refNode parameter is a Node object. The offset parameter is a long object. This method can raise a RangeException object or a DOMException object. setEnd(refNode, offset) This method has no return value. The refNode parameter is a Node object. The offset parameter is a long object. This method can raise a RangeException object or a DOMException object. setStartBefore(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. setStartAfter(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. setEndBefore(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. setEndAfter(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. collapse(toStart) This method has no return value. The toStart parameter is of type Boolean. This method can raise a DOMException object. selectNode(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. selectNodeContents(refNode) This method has no return value. The refNode parameter is a Node object. This method can raise a RangeException object or a DOMException object. compareBoundaryPoints(how, sourceRange) This method returns a short object. The how parameter is of type Number. The sourceRange parameter is a Range object. This method can raise a DOMException object. deleteContents() This method has no return value. This method can raise a DOMException object. extractContents() This method returns a DocumentFragment object. This method can raise a DOMException object. cloneContents() This method returns a DocumentFragment object. This method can raise a DOMException object. insertNode(newNode) This method has no return value. The newNode parameter is a Node object. This method can raise a DOMException object or a RangeException object. surroundContents(newParent) This method has no return value. The newParent parameter is a Node object. This method can raise a DOMException object or a RangeException object. cloneRange() This method returns a Range object. This method can raise a DOMException object. toString() This method returns a String. This method can raise a DOMException object. detach() This method has no return value. This method can raise a DOMException object. Object DocumentRange The DocumentRange object has the following methods: createRange() This method returns a Range object. Prototype Object RangeException The RangeException class has the following constants: RangeException.BAD_BOUNDARYPOINTS_ERR This constant is of type Number and its value is 1. RangeException.INVALID_NODE_TYPE_ERR This constant is of type Number and its value is 2. Object RangeException The RangeException object has the following properties: code This property is of type Number. 13 November, 2000 Appendix D: Acknowledgements Many people contributed to this specification, including members of the DOM Working Group and the DOM Interest Group. We especially thank the following: Lauren Wood (SoftQuad Software Inc., chair), Andrew Watson (Object Management Group), Andy Heninger (IBM), Arnaud Le Hors (W3C and IBM), Ben Chang (Oracle), Bill Smith (Sun), Bill Shea (Merrill Lynch), Bob Sutor (IBM), Chris Lovett (Microsoft), Chris Wilson (Microsoft), David Brownell (Sun), David Singer (IBM), Don Park (invited), Eric Vasilik (Microsoft), Gavin Nicol (INSO), Ian Jacobs (W3C), James Clark (invited), James Davidson (Sun), Jared Sorensen (Novell), Joe Kesselman (IBM), Joe Lapp (webMethods), Joe Marini (Macromedia), Johnny Stenback (Netscape), Jonathan Marsh (Microsoft), Jonathan Robie (Texcel Research and Software AG), Kim Adamson-Sharpe (SoftQuad Software Inc.), Laurence Cable (Sun), Mark Davis (IBM), Mark Scardina (Oracle), Martin Dürst (W3C), Mick Goulish (Software AG), Mike Champion (Arbortext and Software AG), Miles Sabin (Cromwell Media), Patti Lutsky (Arbortext), Paul Grosso (Arbortext), Peter Sharpe (SoftQuad Software Inc.), Phil Karlton (Netscape), Philippe Le Hégaret (W3C, W3C team contact), Ramesh Lekshmynarayanan (Merrill Lynch), Ray Whitmer (iMall, Excite@Home and Netscape), Rich Rollman (Microsoft), Rick Gessner (Netscape), Scott Isaacs (Microsoft), Sharon Adler (INSO), Steve Byrne (JavaSoft), Tim Bray (invited), Tom Pixley (Netscape), Vidur Apparao (Netscape), Vinod Anupam (Lucent). Thanks to all those who have helped to improve this specification by sending suggestions and corrections. D.1: Production Systems This specification was written in XML. The HTML, OMG IDL, Java and ECMA Script bindings were all produced automatically. Thanks to Joe English, author of cost, which was used as the basis for producing DOM Level 1. Thanks also to Gavin Nicol, who wrote the scripts which run on top of cost. Arnaud Le Hors and Philippe Le Hégaret maintained the scripts. For DOM Level 2, we used Xerces as the basis DOM implementation and wish to thank the authors. Philippe Le Hégaret and Arnaud Le Hors wrote the Java programs which are the DOM application. Thanks also to Jan Kärrman, author of html2ps, which we use in creating the PostScript version of the specification. 13 November, 2000 Glossary Editors Arnaud Le Hors, IBM Lauren Wood, SoftQuad Software Inc. Robert S. Sutor, IBM (for DOM Level 1) Several of the following term definitions have been borrowed or modified from similar definitions in other W3C or standards documents. See the links within the definitions for more information. 16-bit unit The base unit of a DOMString. This indicates that indexing on a DOMString occurs in units of 16 bits. This must not be misunderstood to mean that a DOMString can store arbitrary 16-bit units. A DOMString is a character string encoded in UTF-16; this means that the restrictions of UTF-16 as well as the other relevant restrictions on character strings must be maintained. A single character, for example in the form of a numeric character reference, may correspond to one or two 16-bit units. For more information, see [Unicode] and [ISO/IEC 10646]. ancestor An ancestor node of any node A is any node above A in a tree model of a document, where "above" means "toward the root." child A child is an immediate descendant node of a node. deepest The deepest element is that element which is furthest from the root or document element in a tree model of the document. document order The term document order has the same meaning as depth first, pre-order traversal, which is equivalent to the order in which the start tags occur in the text representation of the document. descendant A descendant node of any node A is any node below A in a tree model of a document, where "above" means "toward the root." parent A parent is an immediate ancestor node of a node. sibling Two nodes are siblings if and only if they have the same parent node. tokenized The description given to various information items (for example, attribute values of various types, but not including the StringType CDATA) after having been processed by the XML processor. The process includes stripping leading and trailing white space, and replacing multiple space characters by one. See the definition of tokenized type. 13 November, 2000 References For the latest version of any W3C specification please consult the list of W3C Technical Reports available at http://www.w3.org/TR. F.1: Normative references DOM Level 2 Core W3C (World Wide Web Consortium) Document Object Model Level 2 Core Specification, November 2000. Available at http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113 ECMAScript ECMA (European Computer Manufacturers Association) ECMAScript Language Specification. Available at http://www.ecma.ch/ecma1/STAND/ECMA-262.HTM ISO/IEC 10646 ISO (International Organization for Standardization). ISO/IEC 10646-1:2000 (E). Information technology - Universal Multiple-Octet Coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual Plane. [Geneva]: International Organization for Standardization. Java Sun Microsystems Inc. The Java Language Specification, James Gosling, Bill Joy, and Guy Steele, September 1996. Available at http://java.sun.com/docs/books/jls OMGIDL OMG (Object Management Group) IDL (Interface Definition Language) defined in The Common Object Request Broker: Architecture and Specification, version 2.3.1, October 1999. Available from http://www.omg.org/ Unicode The Unicode Consortium. The Unicode Standard, Version 3.0., February 2000. Available at http://www.unicode.org/unicode/standard/versions/Unicode3.0.html. 13 November, 2000 Index 16-bit unit 1, 2, 3, 4, 5 acceptNode ancestor 1, 2, 3, 4 ancestor container 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 BAD_BOUNDARYPOINTS_ERR before/after/equal to boundary-point 1, 2, 3, 4, 5, 6, 7, 8, 9 child 1, 2, 3, 4 cloneContents cloneRange collapse collapsed 1, 2, 3, 4, commonAncestorContainer 5 container 1, 2, 3, 4, compareBoundaryPoints 5, 6, 7, 8, 9, 10, 11, context tree 1, 2, 3, 4, 5, 12 6, 7 createNodeIterator createRange createTreeWalker currentNode deepest 1, 2 deleteContents descendant 1, 2, 3, 4, 5 detach 1, 2 document order 1, 2 DocumentRange DocumentTraversal DOM Level 2 Core 1, 2, 3, 4 ECMAScript END_TO_END END_TO_START endContainer endOffset expandEntityReferences 1, 2 extractContents filter 1, 2 FILTER_ACCEPT FILTER_REJECT FILTER_SKIP firstChild insertNode INVALID_NODE_TYPE_ERR ISO/IEC 10646 1, 2 Java lastChild nextNode 1, 2 nextSibling NodeFilter NodeIterator offset 1, 2, 3, 4, 5, 6OMGIDL parent 1, 2, 3, 4, 5, 6parentNode partially selected 1, 2, 3, 4, 5, 6 previousNode 1, 2 previousSibling Range RangeException root 1, 2 root container 1, 2, 3, 4, 5 selected 1, 2, 3 selectNode selectNodeContents setEnd setEndAfter setEndBefore setStart setStartAfter setStartBefore SHOW_ALL SHOW_ATTRIBUTE SHOW_CDATA_SECTION SHOW_COMMENT SHOW_DOCUMENT SHOW_DOCUMENT_FRAGMENT SHOW_DOCUMENT_TYPE SHOW_ELEMENT SHOW_ENTITY SHOW_ENTITY_REFERENCE SHOW_NOTATION SHOW_PROCESSING_INSTRUCTION SHOW_TEXT sibling 1, 2, 3, 4, 5, START_TO_END 6 START_TO_START startContainer startOffset surroundContents tokenized toString TreeWalker Unicode 1, 2 whatToShow 1, 2