ContentEditable

from http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-December/024627.html

Dealing with inconsistencies in browser behavior during typing is one of the hardest parts of writing a sane web-based rich-text editor. We have researched what a variety of text editors (Word, Powerpoint, Wordpad, TextEdit) and browsers using contentEditable/DesignMode currently do when you press different keys on the keyboard, in a number of rich text situations, with a variety of text selections. From this data, we attempt to identify recommendations that are OS-agnostic for editing behaviors inside a contentEditable element.

Since we've used a bunch of tables and formatting, we've attached the doc as an HTML file in addition to inline.

Ojan

Julie Parent, Ojan Vafai, Alex Russel, Eric Seidel

About this document

We have researched what a variety of text editors (Word, Powerpoint, Wordpad, TextEdit) and browsers using contentEditable/DesignMode currently do when you press different keys on the keyboard, in a number of rich text situations, with a variety of text selections. From this data, we have identified a set of common behaviors, listed below in the terminology section. Finally, we have formed recommendations for default behaviors in these circumstances and, when necessary, added additional execCommands or specification details to existing execCommands.The execCommands match the behavior of the user-initiated action in order to give developers control over these behaviors when the defaults are incorrect for a specific use case.

We tried to avoid defining any behaviors that are OS-specific and to make the descriptions as clear as possible, but there's a lot of detail here that could use the scrutiny of more eyes. We also tried to make the text as clear as possible, but are not spec writers and don't intend this to be the actual text used in the spec. Please comment on any text that doesn't make sense.

Terminology

Typeable Position: A normalized position (node, offset), for which inserting a character produces valid html. Arrow keys move by typeable positions. Basically, anywhere you can put a character and it isn't an HTML5 error.

Typing style: Internal state of formatting that should be applied when text is inserted. The typing style is automatically emptied when the user modifies the selection (e.g. moves the caret). This is used for things like execCommand('bold') on a collapsed selection.

Caret: Collapsed selection.

Block context: The type of block to use when adding a block during a split.

Legend: Common behaviors

See [#Appendix Appendix] for details on differences in the current implementations of these behaviors.

Short name	Description
Undo: add entry	Adds a new entry to the undo stack
Undo: combine with text	Treat like any other text insertion - UA can group together to form a single entry.
focus next	Contents: nop.Undo: nop.Selection: Focus moved to next tabable item.
focus prev	Like focus next, but moves to the previous item in tab order
focus next cell	Contents: nop.undo: nop.Selection: Focus is moved to the next cell (either next cell in a row, or to the first cell in the next row) Cursor is at start of next cell or cell contents are selected. See below for current details
select(item)	Cause the user visible selection to fully select the item.
indent paragraph(s)	Indent each paragraph individually.Undo: add entrySelection: unchanged
outdent pragraph(s)	If indented, outdent one level.undo: add entryIf not indented, nop.Selection: unchanged
indent li	Contents: See table below for current implementation differences.Undo: add entry.Selection: Cursor is unchanged visibly.
indent list	Contents: Html is no longer list based (this is word only).Undo: add entrySelection: Cursor is unchanged visbily.
insert tab char	Contents: Inserts tab character at typeable caret location.Undo: combined with text.Selection: Caret is after tab char.
insert spaces	Contents: See table below for different implementations of inserting spaces.Undo: combine with text.Selection: Cursor is after the spaces and any tags they added.
insert table row	Contents: Adds a new table rowUndo: add entrySelection: Cursor in first cell of new row
break out	breaks out of the current node and adds a new node of the type of the new context it's in.Note: Anytime a node is split, all copyable properties end up on both nodes (as an example, ID is not copyable since that would leave you with an invalid DOM).
split	splits the current block node at the cursor
split contents	split contents into two nodes of the block context and make them the child of the parent
br	inserts a br
break out and wrap in block	breaks out of the current node and wraps both new nodes in a block of the type of the new block context
split wrap in block	split inlines and wrap in two elements of the block context type
replace selected	Text selected is removed from the document and replaced with new content.Cursor is collapsed at end of the newly inserted text.Undo: Either combine with text or add entry. UA specific.
remove(item)	Removes the item from the dom.If the item removed would create an empty block tag, the UA should insert a non-breaking space that the user is unable to put the cursor after and is automatically deleted when the user types (this is roughly IE's behavior).If the item removed would create an empty inline styling tag, the tag and it's formatting should be removed and entered into the typing style.For backspace: Cursor moves to typeable position before the removed item.For delete: Cursor moves to typeable poistion after the removed item.
maintain styling	Removes an inline styling tag from the dom and adds it to the typing style.Aka, given "a<b>foo</b>c", if you start at the end of "foo", and backspace 3 times, you are left with "ac", but if you insert a "b" before changing the selection, you'd get "a<b>b</b>c".
merge	Merge 2 blocks into 1. The second block (in document order) is merged into the first. The type and styling of the second block are lost.Aka, given <p>paragraph</p><h1>header</h1>, with the cursor at the start of the H1 and pressing backspace results in <p>paragraphheader</p> and the <h1> is lost, and the cursor remains at the merge point, between "paragraph" and "header". For delete, if the cursor is at the end of the P, the result is the same as backspace at the start of the H1.
nop	Nothing happens to contents, selection, undo stack, etc.
delete(rangeContents)	Delete all fully selected nodes and all selected characters, but preserve partially selected nodes. Cursor is collapsed after this action.
no merge	Adjacent blocks are not merged into one block.
merge + wrap styling	Merge adjacent blocks, but wrap the second blocks's contents in a styled span that keeps the original styling and cancels out any styling from the first block.
cursor: end of start	Cursor is located after the last character of the start node, but before the end node. That is, if you type, the inserted character will go into the start node.Note: in all contexts, selection direction does not effect this.
cursor: collapse(toStart)	Collapse the cursor to the start/end.
backwards merge	Merge 2 blocks, but rather than merging second block into first block, merge first block into second block.
no content change	Text contents do not change. Not a total nop since selection can still change.

Key to the tables below

Green: Current behavior matches the recommended behavior.

Red: Current behavior does not match the recommended behavior.

Orange: Current behavior nearly matches the recommended behavior. Difference is usually a platform specific subtlety.

N/A: Behavior does not apply in this context.

Collapsed selections (carets)

Text insertion

[#FOOTNOTE-1 1]

Alphanumerics

Recomendation for HTML 5:

1. Normalize the current caret to a typeable Position.
2. Insert the character at the typeable position.
3. Adjust the typeable position to be collapsed after the inserted text.

execCommand('insertText', false, singleCharacter) should be equivalent to pressing the alphanumeric key on the keyboard. Currently supported by WebKit.

Notes: Current and recommended behaviors match here, and there are no known differences been UA's, other than with undo group formation, white-space rebalancing, and where typeable positions are. Specifically:

• Undo: combine with text (UA specific when to start new groups).
• Need to deal with white-space rebalancing to enable multiple spaces.
• Given a dom with multiple dom positions for the same visible positions, UA's currently vary in which position is considered the typeable position. Example: given foo<b>bar</b>baz:
  • With the cursor between bar and baz (in the way a user can create, not programatically), insertions happen:
    • IE: if you click into the location, text goes into the B tag. If you use arrow keys, it goes outside.
    • FF: If you click in, outside. If you arrow from outside the tag, outside. If you arrow from inside the tag, inside.
    • Chrome: always in.
    • Word: always in.
    • PPT: always in.
  • With the cursor between foo and bar, insertions happen:
    • IE: Click, outside B. Arrows, inside.
    • FF: Click, outside. Arrow from inside the tag, inside. Arrow from outside the tag, outside.
    • Chrome: Always out.
    • Word: always out.
    • PPT: always out.

Paste

Recomendation for HTML 5:

1. Normalize the current caret to a typeable Position.
2. Begin a new undo group
3. Insert the html, performing cleanups to create valid html.
4. End undo group
5. Adjust the typeable position to be collapsed after the inserted text.

execCommand('paste', false, null) should be equivalent to paste from other sources (edit menu, right click, control + v).

Notes:

• Current and recommended behaviors match here, except for cleanups required to create valid html on insert.
• What if the html to insert would be invalid at that given location? Currently, WebKit and IE do no (?) cleanup, and FF does some cleanup to create valid html.
• Example: Pasting a block into an inline: HTML is "<b>fo|o</b>", where | is the cursor. Paste "<h1>bar</h1>".
  • WebKit: <b>fo<span><h1>bar</h1></span>o</b> (INVALID)
  • IE 7: <b>fo<h1>bar</h1>o</b> (INVALID)
  • FF 3: <b>fo</b><h1>bar</h1><b>o</b> (VALID)

Text deletion

#FOOTNOTE-2 2 Notes:

• Undo behavior for deletions matches insertions, that is, multiple insertions|deletions can combine into a single entry.
• In PPT, FF, insertions and deletions do not share an undo group, in Word, IE, Chrome they do.

Backspace

Recommendation for HTML 5:

If cursor at the start of a block, merge with previous block. Otherwise, remove previous item. The table below shows how closely current editors match this recommendation.

execCommand('delete', false, null) should be equivalent to backspace.

Current Default Behaviors and Recommendations:

ContextPrevious item is:	PPT	Word	IE	FF	Chrome	Textedit	Recomendation
text	remove(char)	remove(char)	remove(char)	remove(char)	remove(char)	remove(char)	remove(char)
beginning of P/H/other blocks	merge	merge	merge	merge	merge	merge	merge
image	N/A - PPT doesn't allow images in text	select(image)double backspace: remove(image)	remove(image)	remove(image)	remove(image)	remove(image)	remove(image)
link	unlinks	unlinks	unlinks	remove(char), subsequent insert goes inside link	remove(char), subsequent insert goes out of link	remove(char),subsequent insert goes inside link	remove(char), subsequent insert goes into link (if it still exists)[Informal user study: If the link text and href match, and were auto-linked to begin with, then this should also unlink.]
table	N/A - PPT doesn't allow tables in text	nop	remove(table)	remove(last char in last table cell)	merge into last table cell	merge into last table cell	select(table)[Informal user study: Many users concerned here about an entire table just being deleted by a single backspace action]
single char of styled text	remove(char), maintain styling	remove(char), maintain styling	remove(char), maintain styling	remove(char), maintain styling	remove(char), maintain styling	remove(char), maintain styling	remove(char), maintain styling
table cell	remove(char)cannot step out of cell	remove(char)cannot step out of cell	remove(char)cannot step out of cell	remove(char)cannot step out of cell	if at start of cell, move focus to previous cell (if there is one) or move out of table if in first cellif in first cell of empty row - delete rowNormal:remove(char)	remove(char)cannot step out of cell	remove(char)cannot step out of cell
list - one char in a li	remove(char)li turns into ghost bullet, that will be a bullet if you type into it again but doesn't render as a bulletbackspace in a ghost bullet will remove the bullet	remove(char)	remove(char)	remove(char)	remove(char)	remove(char)	remove(char)
list - before first char	remove(li)	remove(li)	remove(li) + break out	merge	merge	remove(li) + break out	remove(li)Note: Second backspace performs the merge.
list	merge into last li	merge into last li	merge into list, but not into an li	merge into last li	merge into last li	merge into last li	merge into last li
list - empty li	only happens as ghost list, remove(li)	remove(li)	remove(li) + break out	merge	merge	remove(li) + break out	remove(li)

Forward Delete

Recomendation for HTML 5:

A forward delete before an item should be equivalent to a backspace after the item. The table below shows how closely editors match this recommendation. If a row is not included in the table below, then the behavior matches the backspace behavior. For individual cells, (m) = matches the backspace behavior.

execCommand('ForwardDelete') should be equivalent to pressing forward delete key (implemented in Webkit).

Current Default Behaviors and Recommendations:

ContextNext item is:	PPT	Word	IE	FF	Chrome	Textedit	Recomendation
link	remove(char)subsequent insert out of link	select(link)double delete: remove(link)	remove(char)subsequent insert out of link	remove(char)subsequent insert into link(m)	remove(char)subsequent insert out of link(m)	remove(char)subsequent insert out of link(m)	remove(char).Subsequent typing into link (if it still exists)If link text matches href and auto-linked, also unlink.(m)
table	N/A(m)	merge previous content into first table cell	remove(table)(m)	delete first char in first table cell (m)	select(table)double delete: remove(table)	merge first cell contents into previous content. Table remains with no first cell.	select(table)(m)
single char of styled text	remove(char)	remove(char)	remove(char)	remove(char)maintain style(m)	remove(char)maintain style(m)	remove(char)maintain style(m)	remove(char)maintain style(m)
table cell	remove(char)cannot step out of cell(m)	remove(char)cannot step out of cell(m)	remove(char)cannot step out of cell(m)	remove(char)cannot step out of cell(m)	Normal: remove(char)(m)end of cell: nop, unless proceeding empty row, remove(row)	Normal: remove(char)end of cell: deletes cell + merges contents from that cell into next cell. if last cell, merges content after table into last table cell	remove(char)cannot step out of cell(m)
list - one char in a li	enters ghost bullet modeUnlike backspace, further deletes won't remove the ghost	remove(char)(m)	remove(char)(m)	remove(char)(m)	remove(char)(m)	remove(char)(m)	remove(char)(m)
list - after last char in a li	merge	merge	move cursor to start of next li, if there is one, else, merge	merge(m)	merge(m)	move next li and its contents onto this line, so there are two bullets on one line	merge
list	merge	merge	delete list, leave contents of lis intact, just not in lis	merge	merge	move first li and its content onto the line with previous content, so there is a bullet halfway through the line	merge
list - empty li	only happens as ghost list, remove(li)(m)	remove(li)(m)	leave li alone, move cursor down to next li, if there is one, else merge into list	merge(m)	merge(m)	move next li and its contents onto this line.	remove(li)(m)

Cut

For a collapsed selection, this is a noop, it does not modify the undo stack.[#FOOTNOTE-3 3]

Tab Key

[#FOOTNOTE-4 4]

Note: FF 3, IE 7, Chrome 1 always perform focus next for tab, no matter what context. They have been eliminated from the tables to avoid clutter.

General undo philosophy

1. If the tab action does not change contents, the undo stack is not modified.
2. If the tab action causes standard text content changes (inserting spaces, spans with spaces, tab character), then the tab action is added to the undo stack just like any other text insertion and can be combined with other text insertion into a single undo entry as the UA sees fit.
3. If the tab action changes contents, but the contents are more structural change (add table row, indent list item), then this action is added as a single entry to the undo stack.

Recomendation for HTML 5: This is largely context-specific, so recomendations are provided in the far right column of the table below.

execCommand('indent') should be equivalent to tab when listed in the table as "indent li". execCommand('insertText', false, " ") or execCommand('insertText', false, "\t")should be equivalent to tab when listed in the table as "insert tab char/spaces".

Current Default Behaviors and Recommendations:

Context	PPT	Word	WordHTML mode	FF2 (Linux)	Wordpad	TextEdit RTF mode	TextEdit Mac mode	Recommended default behavior
li, with or without text content, cursor at start of li, inside list (not the first li in the list)	indent li	indent li	indent li	indent li	insert tab char	indent li	indent li	indent li
li, with or without text content, cursor at start of li, start of list (first li in list)	indent li	indent list	indent list	indent li	insert tab char	indent li	indent li	indent li
li, with or without content, cursor inside content	insert tab char	insert tab char	insert spaces (8 nbsp + " ")	indent li	insert tab char	insert tab char	insert tab char	insert tab char/spaces
li, with content, cursor at end of li	insert tab char	insert tab char	insert spaces (8 nbsp + " ")	indent li	insert tab char	insert tab char	insert tab char	insert tab char/spaces
table cell - not last cell	focus next cell	focus next cell	focus next cell	focus next cell	focus next cell	focus next cell	focus next cell	focus next cell
table cell - last cell	insert table row	insert table row	insert table row	insert table row	insert table row	move visibly outside of tableif there is a node after table, cursor is thereotherwise, cursor is visibly outside of table, but when you type, goes into last table cell	move visibly outside of tableif there is a node after table, cursor is thereotherwise, cursor is visibly outside of table, but when you type, goes into last table cell	insert table row
PRE	N/A	N/A	insert spaces (5 nbsp + " ")	Insert tab (\t)	N/A	insert tab	converts pre to P, insert spaces	insert tab/spaces
CODE	N/A	N/A	insert spaces (3 nbsp + " ")	Insert spaces	N/A	insert tab	converts code to P, insert spaces	insert tab/spaces
normal rich text text (not plaintext area)	insert tab char	insert tab char	Insert spaces (8 nbsp + " ")	Insert spaces	insert tab char	insert tab char	Insert spaces	insert tab/spaces
plaintextarea	N/A	N/A	N/A	focus next	N/A	N/A	N/A	focus next

Enter

[#FOOTNOTE-5 5]

Recommendation for HTML 5:

This is largely context-specific, so recomendations are provided in the far right column of the table below. Undo behaves the same as regular text insertion. (shift|option)+enter: Always inserts a br.

execCommand('SplitBlock', false, blockTagName): Performs the split command. Walks up the tree to find the first parent block and splits all the nodes from the cursor to that block maintaining all attributes on the split nodes, including inline styling. If one of the nodes being split is an anchor tag, the anchor should not be included in the second half. Stops at the first table-cell or contentEditable ancestor. If there is no parent block between the caret and the first table-cell/contentEditable ancestor, then it wraps the inline contents before and after the selection in an element of type blockTagName.

We stop at the first table-cell ancestor because splitting it does not actually perform the user-expected behavior of adding a new block.

If any nodes that are split have an ID, then the ID is not added to the second node after the split.In the table below, this command is listed below as "split", "split contents", "split wrap in block", and "break out and wrap block".

execCommand('SplitOutOfBlock', false, blockTagName): Performs a split command and changes the type of the second block to that of blockTagName.

In both commands above, blockTagName defaults to 'DIV'. This matches the WebKit behavior as opposed to the IE behavior of defaulting to 'P'. DIV makes more sense to users as it matches other word processor behavior of not having default margins. Also, it is semantically more accurate as the UA does not know what the user intends to put inside the element.In the table below, this command maps to "break out".

execCommand('InsertBreak', false, null): Inserts a BR element.

Current Default Behaviors and Recommendations

Context	PPT 2008Mac	Word 2008 Mac Doc mode	Word 2008 Mac HTML mode	IE 7	FF 3 - Win	Chrome	Wordpad	textedit Mac RTF mode	textedit Mac HTML mode	Recommended default behavior
end of header	n/a	break out	break out	break out	break out and insert two brs	break out	n/a	n/a	split and add a bunch of styling	break out
beginning/middle of header	n/a	split	split	split	split	split	n/a	n/a	split and add a bunch of styling	split
paragraphs	split	split	split	split	split	split	split	split	split	split
table cell	split contents	split contents	split contents	split contents	br	br	split	split contents	split contents	split contents
div	n/a	n/a	split contents	split	br	split	n/a	n/a	turn everything into p with styling	split
li	split	split	split	split	split	split	split	split	split	split
empty li	split with placeholder list item	break out (see footnote)	break out (see footnote)	break out	break out	break out	break out and add two line breaks	break out	break out	break out
empty li in nested list	split with placeholder list item	break out	break out	break out	break out	break out	n/a	break out	break out	break out
inlines	maintained	maintained	spilt wrap in block	split wrap in block	br	br	maintained	maintained	maintained	split wrap in block
link	split	open link	open link	break out and wrap in block	br	br	n/a	split	split	break out and wrap block
blockquote	n/a	n/a	split contents	split contents	br	split	n/a	n/a	turn everything into p with styling	split
pre	n/a	split	split	split	br	split	n/a	n/a	turn everything into p with styling	br

Non collapsed selections

Text insertion

[#FOOTNOTE-6 6]

Notes: Undo behavior is the same as collapsed case.

Alphanumerics

Recomendation for HTML 5: Equivalent to backspace + insert (execCommand('delete') + execCommand('insertText')) on collapsed selection.

Paste

Recomendation for HTML 5: Equivalent to backspace + paste (execCommand('delete') + execCommand('insertHTML')) on collapsed selection.

Text deletion

[#FOOTNOTE-7 7]

Backspace

Recomendation for HTML 5:

Always delete the contents of the selected range. Unless a table cell is one of the endpoints, merge into the previous element, but preserve style from the second.

execCommand('delete') with a range selected should be equivalent to backspace with the same range selected.

Current Default Behaviors and Recommendations

Start node	End node	PPT	Word	IE	FF	Chrome	TextEdit	Recommendation
Text	Text	delete(rangeContents)	delete(rangeContents)	delete(rangeContents)	delete(rangeContents)	delete(rangeContents)	delete(rangeContents)	delete(rangeContents)
inline	inline	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start	delete(rangeContents)cursor: end of start
DEFAULT BACKSPACEinline/block/header/li(any combo that isn't inline to inline)	DEFAULT BACKSPACEinline/block/header/li(any combo that isn't inline to inline)	delete(rangeContents)merge + preserve stylingcursor: end of start	delete(rangeContents)no mergecursor: end of startNote: Word 2003delete(rangeContents) + backwards merge	delete(rangeContents)merge + preserve stylingcursor: end of start	delete(rangeContents)no mergecursor: end of start	delete(rangeContents)merge + preserve stylingcursor: end of start	delete(rangeContents)merge + preserve stylingcursor: end of start	delete(rangeContents)merge + preserve stylecursor: end of start
inline/block	table cell	N/A	delete(rangeContent)backwards mergecursor: end of start	no content changecursor: collapse(true)	DEFAULT BACKSPACE	delete(rangeContents)no mergecursor: end of start	delete(rangeContents)no mergecursor: start of end	delete(rangeContents)no mergecursor: end of start
table cell	inline/block	N/A	delete(rangeContents)no mergecursor: start of end	no content changecursor: collapse(true)	DEFAULT BACKSPACE	DEFAULT BACKSPACE	delete(rangeContents)no mergecursor: start of end, but once you type, contents jump back up into table cell.	delete(rangeContents)no mergecursor: end of start
table cell	table cell	delete cell contentscursor: collapse(true)	UI prompt - delete entire row|column, shift cells up|left(unless table cells are in different tables, then does delete(rangeContents) + merge)	no content changecursor: collapse(true)	DEFAULT BACKSPACE	delete(rangeContents)no mergecursor: end of start	delete(rangeContents)no mergecursor: start of end,but if you type, cells merge	delete(rangeContents)no mergecursor: end of start
li	li	DEFAULT BACKSPACE	DEFAULT BACKSPACE[#FOOTNOTE-8 8]	DEFAULT BACKSPACE	delete(rangeContents)merge	DEFAULT BACKSPACE	DEFAULT BACKSPACE	DEFAULT BACKSPACE

Delete

Recommendation for HTML 5:

Like in the collapsed cursor case, delete and backspace should be the same.

Current exceptions:

• Firefox, only change is in cursor placement. With backspace, cursor goes at the end of the start node. With delete, it goes at the start of the end node. This subtle change is noticeable when you type after performing a backspace/delete - does it take the style of the first or second original node?
• IE, only change is with table cells. With backspace, contents are not changed, but the cursor is collapsed. With delete, it is a complete nop.
• Word, only change is with table cell to table cell selection. With backspace, a prompt is raised with several options on what to do (delete entire row, delete entire column, shift cells up, etc). With delete, the cell contents are just deleted and the cursor is collapsed to start.
• IE 8 is different from IE 7 for both backspace and delete cases. The tables above show IE 7 behavior. Biggest difference is that IE 8 uses directionality information and does different cursor placement for backspace/delete. Behavior seems to be: forward selection + backspace: end of start, forward selection + delete, backward selection + backspace, backwards selection + delete: start of end

execCommand('ForwardDelete') with a range selected should be equivalent to delete with the same range selected.

Tab

[#FOOTNOTE-9 9]

Notes:

• FF 3, IE 7, Chrome 1 always perform focus next for tab, no matter what context. They have been eliminated from the tables below to avoid clutter.
• I've combined Word in Doc mode and HTML mode into one column. Only differences are with tab vs spaces.

Recommendation for HTML 5:

This is largely context-specific, so recomendations are provided in the far right column of the table below.

execCommand('insertText', false, ' ' | '\t') should be equivalent to "replace selected(tab|spaces)" with the same range selected, which should be equivalent to calling execCommand('Delete') and then execCommand('insertText').

The assorted indent behaviors should be equivalent to execCommand('indent') when given the same selection, likewise, for the outdent behaviors and execCommand('outdent').

Current Default Behaviors and Recommendations:

Context	PPT 2003WinPPT2007Win	Word 2003 Win Doc/HTML modeWord 2007 Doc/HTML Mode	FF2 (linux)	Wordpad	TextEdit Mac	Recommended default behavior
Text content selected, inside a single paragraph	replace selected(tab)	replace selected(tab |10 spaces)	replace selected(4 spaces)	replace selected(tab)	replace selected(tab)	replace selected(tab|spaces)
Text content selected, inside a single paragraph, SHIFT+TAB	replace selected(tab)	replace selected(tab | 10 spaces)	focus prev	replace selected(tab)	nop	replace selected(tab|spaces)
Text content selected, span 2 paragraphs partially	indent paragraphs	Delete selectedindent paragraphcursor collapsed to start of paragraphundo: add entry(delete)add entry(indent)	replace selected(4 spaces)	replace selected(tab)	replace selected(space)	indent paragraphs
Text content selected, span 2 paragraphs partially, SHIFT + Tab	outdent paragraph	delete selectedoutdent paragraphcollapse cursor to start of paragraphundo: add entry(delete)add entry(outdent)	focus prev	replace selected(tab)	nop	outdent paragraphs
Text content, full paragraph(s)selected	indent paragraph(s)	indent paragraph(s)	replace selected(4 spaces)	replace selected(tab)	replace selected(tab)	indent paragraph(s)
text content, full paragraph(s) selected, SHIFT + TAB	outdent paragraph(s)	outdent paragraph(s)	focus prev	replace selected(tab)	nop	outdent paragraph(s)
text content, select 2 paragraphs, first paragraph fully selected, second partial	indent paragraphs	indent paragraphs	replace selected(4 spaces)	replace selected(tab)	replace selected(tab)	indent paragraphs
text content, select 2 paragraphs, first paragraph fully selected, second partial, SHIFT + TAB	outdent paragraphs	outdent paragraphs	focus prev	replace selected(tab)	nop	outdent paragraphs
text content, select 2 paragraphs, first paragraph partially selected, second fully	indent paragraphs	replace selected(tab | 10 spaces)	replace selected(4 spaces)	replace selected(tab)	replace selected(space)	indent paragraphs
text content, select 2 paragraphs, first paragraph partially selected, second fully, SHIFT + TAB	outdent paragraphs	replace selected(tab | 10 spaces)	focus prev	replace selected(tab)	nop	outdent paragraphs
contained inside single li	replace selected(tab)	replace selected(tab | 7 spaces)	indent liORindent just the text node containing the selection. Seems to depend on underlying html.	replace selected(tab)	replace selected(tab)	replace selected(tab | spaces)
contained inside single li, SHIFT + TAB	replace selected(tab)	replace selected(tab | 7 spaces)	outdent	replace selected(tab)	outdent	replace selected(tab | spaces)
partially spanning multiple li	indent lis	delete selectedindent licursor at start of liundo: add entry(delete)add entry(indent li)	indent lis	replace selected(tab)	replace selected(tab)	indent lis
partially spanning multiple li, SHIFT + TAB	outdent lis	delete selectedoutdent licursor at start of liundo: add entry(delete)add entry (outdent li) or add entry (move cursor)	outdent lis	replace selected(tab)	outdent first li (regardless of direction)cursor collapsed at start of second li, no matter ohw many selected	outdent lis
li(s) fully selected	indent li(s)	indent li(s) ORif contains first li, indent list	indent li(s)	replace selected(tab)	if one: indent li, collapse cursor to start of liif multiple: indent first li, collapse cursor to start of second li	indent li(s)
li(s) fully selected, SHIFT + TAB	outdent li(s)	outdent li(s) OR if contsint the first li, outdent list	outdent li(s)	replace selected(tab)	if one: outdent liif multiple: outdent first li, collapse cursor to start of second li	outdent li(s)
spanning multiple li's, first li fully selected	indent lis	indent lis ORif contains first li, indent list	indent lis	replace selected(tab)	indent first li	indent lis
spanning multiple li's, first li fully selected,SHIFT + TAB	outdent lis	outdent li(s)	outdent lis	replace selected(tab)	outdent first li	outdent lis
spanning multiple li's, first li not fully selected	indent lis	delete selectedindent licursor at start of liundo: add entry(delete)add entry(indent)	indent lis	replace selected(tab)	replace selected(tab)	indent lis
spanning multiple li's, first li not fully selected, SHIFT + TAB	outdent lis	delete selectedoutdent licursor at start of liundo: add entry(delete)add entry(outdent) or addentry(move cursor)	outdent lis	replace selected(tab)	outdent first li	outdent lis
table cell - inside one cell	focus next cell / insert table row (same as collapsed)	focus next cell / insert table row (same as collapsed)	focus next cell / insert table row	focus next cell / insert table row	focus next cell / move to next line	focus next cell / insert table row
table cell - span 2 cells	cannot select partial multiple cellsfocus moves to first cell in selection, and that cell is fully selected	cannot select partial multiple cellsfocus moves to first cell in selection, and that cell is fully selected	focus moves to second selected cell.cursor collapsed	cannot select partial multiple cellsforward selection: focus is moved 2 cells past the last selected cell, cell is fully selectedbackwards selection: focus is moved 1 cel past the last selected cell (document order), cell is fully selectedinsert table row if focus would move to cell in a row that doesn't exist	collapse cursor to start of second cell, no matter how many selected	focus next cell
PRE	N/A	replace (3 spaces)	replace (\t)	N/A	replace (\t)	replace (tab | spaces)
CODE	N/A	replace (1 space)	replace (4 spaces)	N/A	replace (\t)

Enter

[#FOOTNOTE-10 10]

Recomendation for HTML 5:

Perform a delete then an enter (as defined above in Part I). No exceptions. Undo: Behaves the same as regular text insertion. (shift|option) + enter: inserts a br.

Notes:

• Word 2008 - Basically the same as a backspace (not a forward-delete) followed by an enter. It does something different if the text is selected via an undo command (it pretends the selection is collapsed at the end of the selection). It also does something different for tables. Iff the selection is partially in a table then the selection is just collapsed to the beginning. If the selection spans multiple TDs, then the selection is shrunk down to the first TD and then a regular enter is performed within that TD.
• Behaviors are marked green in the table below if they match this recommendation even if their delete or enter implementations do not match those recommendations.

Current Default Behaviors:

Context	Word 2008 Mac Doc and HTML mode	IE 7	FF 3 - Win	Chrome	Wordpad	textedit Mac RTF/HTML mode
Base behavior	backspace (not forward-delete), then caret enter - maintain inline formatting	Delete then caret enter - maintain inline formatting	Delete then caret enter - inconsistent about maintaining inline formatting, but mostly does not keep any	Delete then caret enter - maintains some inline formatting (e.g. sometimes loses background-color)	Delete then caret enter except it loses inline formatting	Delete/backspace then caret enter - maintain inline formatting
After Undo/Redo	Collapse to end of the selection, then perform enter.
Selection starts before table ends in table	Just collapse to beginning of selection.	noop	Delete all the text in the TDs, truncate selection to not include the table, do a regular delete+enter	Delete all the text in the TDs, truncate selection to not include the table, do a regular delete+enter	delete + enter	Shrink selection to end just before the table and perform enter
Entire table row selected	deletes the contents of the first selected cell, collapses cursor in that cell, then performs enter	nop	delete all text in the tds, collapse to start, regular delete + enter	Any time a selection contains an entire table row, enter deletes that row	delete row
Selection starts in a table and ends after it	Deletes the selected rows, performs a backspace, then enter.	noop	Delete all the text in the TDs and the nodes selected after the table, then perform enter in the first TD	Delete all the text in the TDs and the nodes selected after the table, then perform enter in the first TD	delete + enter	Shrink selection to end at the end of the first TD selected and perform enter.
Selection spans multiple TDs	Collapse the selection to the first TD and then perform enter.	noop	Delete all the TD's contents and perform enter in the first TD	Delete all the TD's contents and perform enter in the first TD	move selection to first cell not in selection, perform enter	Shrink selection to end at the end of the first TD selected and perform enter.
Entire table-contents selected	Delete the table and then perform enter.	noop	Delete table contents	Delete the table and perform enter.	delete the table + enter	Delete all the TDs in the table and leave just one TD, then perform enter.
Entire table selected	Delete the table and then perform enter.	Delete the table and perform enter.	Delete table perform enter	Delete the table and perform enter.	delete + enter	Delete the table and perform enter.
link	Delete, then split the link (not delete + enter, since enter in a link in word navigates to the link)	delete + enter	delete + enter	delete + enter	delete + enter
li contents	delete + enter	delete + enter	delete + enter	Delete + enter	if fully selected,delete li contents, add a new liif partial selection,delete + enter
node contents + line break after li				delete then enter, but the delete does funky things

Appendix

Common Behavior Implementation Differences and Recomendations

Context	PPT	Word	WordHTML mode	FF2 (Linux)	Wordpad	TextEdit RTF mode	TextEdit Mac mode	Recommended default behavior
indent li	if one type of list - follow typeif mixed types but indenting one type-follows type of li being indentedif mixed types, indenting mixed types-follows mixed types (not collapsed cursor)	one type -follows typemixed types, single type selected - follows top typemixed types, multiple types selected - follows mixed types(not collapsed cursor)	one type -follows typemixed types, single type selected - follows top typemixed types, multiple types selected - follows mixed types(not collapsed cursor)	if one type - follow typemixed types, single type selected-follow typemixed types, mixed types selected -follows mixed types(not collapsed cursor)	N/A	always UL	always UL	if one type - follow typeif mixed type - follow selected type
insert spaces	N/A	N/A	Inserts a span with spaces (variable # &nbsp):<span style='mso-tab-count:1'> </span>	"    " or "   <br>" if end of block.	N/A	N/A	<span> </span>	UA specific
focus next cell	moves focus to next table cell (next cell in row or first cell in next row)selects all text in that cell	moves focus to next table cell (next cell in row or first cell in next row)selects all text in that cell	moves focus to next table cell (next cell in row or first cell in next row)selects all text in that cell	focus moves to next table cellcursor collapsed at start of that cell	moves focus to next table cell (next cell in row or first cell in next row)selects all text in that cell	moves focus to next table cellcursor collapsed at start of cell	moves focus to next table cellcursor collapsed at start of cell	moves focus to next table cellcursor selecting all text in cell

Notes

1) For more details, see Eric's original research.

2) For more details, see Eric's original research and Julie's original research. In this section, data is from Chrome 2.0.170.0.

3) Tested on IE 7, FF 3, Chrome 2, Word 2003, all on Windows.

4) For more details, see Julie's original research

5) For more details, see Ojan's original research

6) For more details, see Eric's original research and Julie's original research.

7) For more details, see Eric's original research and Julie's original research.

8) Does perform this UA's DEFAULT BACKSPACE behavior, but that doesn't match recommended DEFAULT BACKSPACE behavior.

9) For more details, see Julie's original research.

10) For more details, see Ojan's original research