A browsing context is an environment in which
Document
objects are presented to the user.
A tab or window in a Web browser typically contains
a browsing context, as does an iframe
.
Each browsing context has a corresponding
WindowProxy
object.
A browsing context has a session
history, which lists the Document
objects that
that browsing context has presented, is presenting, or
will present. At any time, one Document
in each
browsing context is designated the active
document. A Document
's browsing
context is that browsing context whose
session history contains the Document
, if
any. (A Document
created using an API such as createDocument()
has no browsing context.)
Each Document
is associated with a
Window
object. A browsing context's
WindowProxy
object forwards everything to the
browsing context's active document's
Window
object.
In general, there is a 1-to-1 mapping from the
Window
object to the Document
object.
There are two exceptions. First, a Window
can be reused
for the presentation of a second Document
in the same
browsing context, such that the mapping is then 2-to-1.
This occurs when a browsing context is navigated from the initial
about:blank
Document
to another, with
replacement enabled. Second, a Document
can end up being reused for several Window
objects when
the document.open()
method is
used, such that the mapping is then 1-to-many.
A Document
does not necessarily have a
browsing context associated with it. In particular,
data mining tools are likely to never instantiate browsing
contexts.
A browsing context can have a creator browsing context, the browsing context that was responsible for its creation. If a browsing context has a parent browsing context, then that is its creator browsing context. Otherwise, if the browsing context has an opener browsing context, then that is its creator browsing context. Otherwise, the browsing context has no creator browsing context.
If a browsing context A has a
creator browsing context, then the
Document
that was the active document of
that creator browsing context at the time A was created is the creator
Document
.
Certain elements (for example, iframe
elements) can
instantiate further browsing
contexts. These are called nested browsing contexts. If a browsing context P has a Document
D
with an element E that nests another browsing
context C inside it, then C
is said to be nested
through D, and E is
said to be the browsing context container of C. If the browsing context container
element E is in the Document
D,
then P is said to be the parent browsing
context of C and C is
said to be a child browsing context of P. Otherwise, the nested browsing
context C has no parent browsing
context.
A browsing context A is said to be an ancestor of a browsing context B if there exists a browsing context A' that is a child browsing context of A and that is itself an ancestor of B, or if there is a browsing context P that is a child browsing context of A and that is the parent browsing context of B.
A browsing context that is not a nested browsing context has no parent browsing context, and is the top-level browsing context of all the browsing contexts for which it is an ancestor browsing context.
The transitive closure of parent browsing contexts for a nested browsing context gives the list of ancestor browsing contexts.
The list of the descendant browsing contexts of a
Document
d is the (ordered) list
returned by the following algorithm:
Let list be an empty list.
For each child browsing context of d that is nested through an element that is in the Document
d, in the tree order of the elements
nesting those browsing
contexts, run these substeps:
Append that child browsing context to the list list.
Append the list of the descendant browsing contexts of the active document of that child browsing context to the list list.
Return the constructed list.
A Document
is said to be fully active
when it is the active document of its browsing
context, and either its browsing context is a top-level
browsing context, or it has a parent browsing
context and the Document
through which it is nested is itself fully
active.
Because they are nested through an element, child browsing contexts are always tied to
a specific Document
in their parent browsing
context. User agents must not allow the user to interact with
child browsing contexts
of elements that are in Document
s that are not
themselves fully active.
A nested browsing context can have a seamless
browsing context flag set, if it is embedded through an
iframe
element with a seamless
attribute.
A nested browsing context can in some
cases be taken out of its parent browsing context (e.g.
if an iframe
element is removed from its
Document
). In such a situation, the nested
browsing context has no parent browsing context,
but it still has the same browsing context container
and is still nested
through that element's Document
. Such a
nested browsing context is not a
top-level browsing context, and cannot contain
Document
s that are fully active.
Furthermore, if a browsing context container (such as
an iframe
) is moved to another Document
,
then the parent browsing context of its nested
browsing context will change.
top
Returns the WindowProxy
for the top-level browsing context.
parent
Returns the WindowProxy
for the parent browsing context.
frameElement
Returns the Element
for the browsing context container.
Returns null if there isn't one.
Throws a SecurityError
exception in cross-origin situations.
It is possible to create new browsing contexts that are related to a top-level browsing context without being nested through an element. Such browsing contexts are called auxiliary browsing contexts. Auxiliary browsing contexts are always top-level browsing contexts.
An auxiliary browsing context has an opener browsing context, which is the browsing context from which the auxiliary browsing context was created.
The opener
IDL
attribute on the Window
object, on getting, must return
the WindowProxy
object of the browsing
context from which the current browsing context
was created (its opener browsing context), if there is
one, if it is still available, and if the current browsing
context has not disowned its opener; otherwise, it
must return null. On setting, if the new value is null then the
current browsing context must disown its opener; if the new value is anything else
then the user agent must ignore the new value.
User agents may support secondary browsing contexts, which are browsing contexts that form part of the user agent's interface, apart from the main content area.
Browsing contexts can have a browsing context name. By default, a browsing context has no name (its name is not set).
A valid browsing context name is any string with at least one character that does not start with a U+005F LOW LINE character. (Names starting with an underscore are reserved for special keywords.)
A valid browsing context name or keyword is any string
that is either a valid browsing context name or that is
an ASCII case-insensitive match for one of: _blank
, _self
, _parent
, or _top
.
These values have different meanings based on whether the page is sandboxed or not, as summarized in the following (non-normative) table. In this table, "current" means the browsing context that the link or script is in, "parent" means the parent browsing context of the one the link or script is in, "master" means the nearest ancestor browsing context of the one the link or script is in that is not itself in a seamless iframe, "top" means the top-level browsing context of the one the link or script is in, "new" means a new top-level browsing context or auxiliary browsing context is to be created, subject to various user preferences and user agent policies, "maybe new" means the same as "new" but the requirements for those cases encourage user agents to treat it more like "none", and "none" means that by default nothing will happen.
Keyword | Ordinary effect | Effect in an iframe with...
| ||||
---|---|---|---|---|---|---|
seamless=""
| sandbox=""
| sandbox="" seamless=""
| sandbox="allow-top-navigation"
| sandbox="allow-top-navigation" seamless=""
| ||
none specified, for links and form submissions | current | master | current | master | current | master |
none specified, for window.open()
| new | new | maybe new† | maybe new† | maybe new† | maybe new† |
empty string | current | master | current | master | current | master |
_blank
| new | new | maybe new | maybe new | maybe new | maybe new |
_self
| current | current | current | current | current | current |
_parent if there isn't a parent
| current | current | current | current | current | current |
_parent if parent is also top
| parent/top | parent/top | none | none | parent/top | parent/top |
_parent if there is one and it's not top
| parent | parent | none | none | none | none |
_top if top is current
| current | current | current | current | current | current |
_top if top is not current
| top | top | none | none | top | top |
name that doesn't exist | new | new | maybe new | maybe new | maybe new | maybe new |
name that exists and is a descendant | specified descendant | specified descendant | specified descendant | specified descendant | specified descendant | specified descendant |
name that exists and is current | current | current | current | current | current | current |
name that exists and is an ancestor that is top | specified ancestor | specified ancestor | none | none | specified ancestor/top | specified ancestor/top |
name that exists and is an ancestor that is not top | specified ancestor | specified ancestor | none | none | none | none |
† This case is only possible if the sandbox
attribute also allows
scripts.
Window
object[ReplaceableNamedProperties] interface Window : EventTarget { // the current browsing context [Unforgeable] readonly attribute WindowProxy window; [Replaceable] readonly attribute WindowProxy self; [Unforgeable] readonly attribute Document document; attribute DOMString name; [PutForwards=href, Unforgeable] readonly attribute Location location; readonly attribute History history; [Replaceable] readonly attribute BarProp locationbar; [Replaceable] readonly attribute BarProp menubar; [Replaceable] readonly attribute BarProp personalbar; [Replaceable] readonly attribute BarProp scrollbars; [Replaceable] readonly attribute BarProp statusbar; [Replaceable] readonly attribute BarProp toolbar; attribute DOMString status; void close(); void stop(); void focus(); void blur(); // other browsing contexts [Replaceable] readonly attribute WindowProxy frames; [Replaceable] readonly attribute unsigned long length; [Unforgeable] readonly attribute WindowProxy top; attribute WindowProxy? opener; readonly attribute WindowProxy parent; readonly attribute Element? frameElement; WindowProxy open(optional DOMString url, optional DOMString target, optional DOMString features, optional boolean replace); getter WindowProxy (unsigned long index); getter object (DOMString name); // the user agent readonly attribute Navigator navigator; readonly attribute External external; readonly attribute ApplicationCache applicationCache; // user prompts void alert(DOMString message); boolean confirm(DOMString message); DOMString? prompt(DOMString message, optional DOMString default); void print(); any showModalDialog(DOMString url, optional any argument); // event handler IDL attributes [TreatNonCallableAsNull] attribute Function? onabort; [TreatNonCallableAsNull] attribute Function? onafterprint; [TreatNonCallableAsNull] attribute Function? onbeforeprint; [TreatNonCallableAsNull] attribute Function? onbeforeunload; [TreatNonCallableAsNull] attribute Function? onblur; [TreatNonCallableAsNull] attribute Function? oncanplay; [TreatNonCallableAsNull] attribute Function? oncanplaythrough; [TreatNonCallableAsNull] attribute Function? onchange; [TreatNonCallableAsNull] attribute Function? onclick; [TreatNonCallableAsNull] attribute Function? oncontextmenu; [TreatNonCallableAsNull] attribute Function? oncuechange; [TreatNonCallableAsNull] attribute Function? ondblclick; [TreatNonCallableAsNull] attribute Function? ondrag; [TreatNonCallableAsNull] attribute Function? ondragend; [TreatNonCallableAsNull] attribute Function? ondragenter; [TreatNonCallableAsNull] attribute Function? ondragleave; [TreatNonCallableAsNull] attribute Function? ondragover; [TreatNonCallableAsNull] attribute Function? ondragstart; [TreatNonCallableAsNull] attribute Function? ondrop; [TreatNonCallableAsNull] attribute Function? ondurationchange; [TreatNonCallableAsNull] attribute Function? onemptied; [TreatNonCallableAsNull] attribute Function? onended; [TreatNonCallableAsNull] attribute Function? onerror; [TreatNonCallableAsNull] attribute Function? onfocus; [TreatNonCallableAsNull] attribute Function? onhashchange; [TreatNonCallableAsNull] attribute Function? oninput; [TreatNonCallableAsNull] attribute Function? oninvalid; [TreatNonCallableAsNull] attribute Function? onkeydown; [TreatNonCallableAsNull] attribute Function? onkeypress; [TreatNonCallableAsNull] attribute Function? onkeyup; [TreatNonCallableAsNull] attribute Function? onload; [TreatNonCallableAsNull] attribute Function? onloadeddata; [TreatNonCallableAsNull] attribute Function? onloadedmetadata; [TreatNonCallableAsNull] attribute Function? onloadstart; [TreatNonCallableAsNull] attribute Function? onmessage; [TreatNonCallableAsNull] attribute Function? onmousedown; [TreatNonCallableAsNull] attribute Function? onmousemove; [TreatNonCallableAsNull] attribute Function? onmouseout; [TreatNonCallableAsNull] attribute Function? onmouseover; [TreatNonCallableAsNull] attribute Function? onmouseup; [TreatNonCallableAsNull] attribute Function? onmousewheel; [TreatNonCallableAsNull] attribute Function? onoffline; [TreatNonCallableAsNull] attribute Function? ononline; [TreatNonCallableAsNull] attribute Function? onpause; [TreatNonCallableAsNull] attribute Function? onplay; [TreatNonCallableAsNull] attribute Function? onplaying; [TreatNonCallableAsNull] attribute Function? onpagehide; [TreatNonCallableAsNull] attribute Function? onpageshow; [TreatNonCallableAsNull] attribute Function? onpopstate; [TreatNonCallableAsNull] attribute Function? onprogress; [TreatNonCallableAsNull] attribute Function? onratechange; [TreatNonCallableAsNull] attribute Function? onreset; [TreatNonCallableAsNull] attribute Function? onresize; [TreatNonCallableAsNull] attribute Function? onscroll; [TreatNonCallableAsNull] attribute Function? onseeked; [TreatNonCallableAsNull] attribute Function? onseeking; [TreatNonCallableAsNull] attribute Function? onselect; [TreatNonCallableAsNull] attribute Function? onshow; [TreatNonCallableAsNull] attribute Function? onstalled; [TreatNonCallableAsNull] attribute Function? onstorage; [TreatNonCallableAsNull] attribute Function? onsubmit; [TreatNonCallableAsNull] attribute Function? onsuspend; [TreatNonCallableAsNull] attribute Function? ontimeupdate; [TreatNonCallableAsNull] attribute Function? onunload; [TreatNonCallableAsNull] attribute Function? onvolumechange; [TreatNonCallableAsNull] attribute Function? onwaiting; };
window
frames
self
These attributes all return window.
document
Returns the active document.
defaultView
Returns the Window
object of the active document.
open
( [ url [, target [, features [, replace ] ] ] ] )Opens a window to show url (defaults to
about:blank
), and returns it. The target argument gives the name of the new
window. If a window exists with that name already, it is
reused. The replace attribute, if true, means
that whatever page is currently open in that window will be
removed from the window's session history. The features argument is ignored.
name
[ = value ]Returns the name of the window.
Can be set, to change the name.
close
()Closes the window.
stop
()Cancels the document load.
length
Returns the number of child browsing contexts.
Returns the indicated child browsing context.
Window
objectReturns the indicated element or collection of elements.
To allow Web pages to integrate with Web browsers, certain Web browser interface elements are exposed in a limited way to scripts in Web pages.
Each interface element is represented by a BarProp
object:
interface BarProp { attribute boolean visible; };
locationbar
. visible
Returns true if the location bar is visible; otherwise, returns false.
menubar
. visible
Returns true if the menu bar is visible; otherwise, returns false.
personalbar
. visible
Returns true if the personal bar is visible; otherwise, returns false.
scrollbars
. visible
Returns true if the scroll bars are visible; otherwise, returns false.
statusbar
. visible
Returns true if the status bar is visible; otherwise, returns false.
toolbar
. visible
Returns true if the toolbar is visible; otherwise, returns false.