Source code
Revision control
Copy as Markdown
Other Tools
BrowsingContext and WindowContext
=================================
The ``BrowsingContext`` is the Gecko representation of the spec-defined
`Browsing Context`_ object.
The Browsing Context Tree
-------------------------
``BrowsingContext`` and ``WindowContext`` objects form a tree, corresponding
to the tree of frame elements which was used to construct them.
Example
^^^^^^^
Loading the HTML documents listed here, would end up creating a set of BrowsingContexts and WindowContexts forming the tree.
.. code-block:: html
<iframe src="frame1.html"></iframe>
<iframe></iframe>
<iframe></iframe>
.. digraph:: browsingcontext
node [shape=rectangle]
"BC1" [label="BrowsingContext A"]
"BC2" [label="BrowsingContext B"]
"BC3" [label="BrowsingContext C"]
"BC4" [label="BrowsingContext D"]
"BC5" [label="BrowsingContext E"]
"BC6" [label="BrowsingContext F"]
"WC5" [label="WindowContext\n(about:blank)"]
"WC6" [label="WindowContext\n(about:blank)"]
"BC1" -> "WC1";
"WC1" -> "BC2";
"WC1" -> "BC3";
"BC2" -> "WC2";
"BC3" -> "WC3";
"WC2" -> "BC4";
"BC4" -> "WC4";
"WC3" -> "BC5";
"BC5" -> "WC5";
"WC3" -> "BC6";
"BC6" -> "WC6";
Synced Fields
-------------
API Documentation
-----------------
.. cpp:class:: BrowsingContext
.. hlist::
:columns: 3
* `header (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/BrowsingContext.h>`_
* `source (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/BrowsingContext.cpp>`_
This is a synced-context type. Instances of it will exist in every
"relevant" content process for the navigation.
Instances of :cpp:class:`BrowsingContext` created in the parent processes
will be :cpp:class:`CanonicalBrowsingContext`.
.. cpp:function:: WindowContext* GetParentWindowContext()
Get the parent ``WindowContext`` embedding this context, or ``nullptr``,
if this is the toplevel context.
.. cpp:function:: WindowContext* GetTopWindowContext()
Get the toplevel ``WindowContext`` embedding this context, or ``nullptr``
if this is the toplevel context.
This is equivalent to repeatedly calling ``GetParentWindowContext()``
until it returns nullptr.
.. cpp:function:: BrowsingContext* GetParent()
.. cpp:function:: BrowsingContext* Top()
.. cpp:function:: static already_AddRefed<BrowsingContext> Get(uint64_t aId)
Look up a specific ``BrowsingContext`` by it's unique ID. Callers should
check if the returned context has already been discarded using
``IsDiscarded`` before using it.
.. cpp:class:: CanonicalBrowsingContext : public BrowsingContext
.. hlist::
:columns: 3
* `header (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/CanonicalBrowsingContext.h>`_
* `source (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/CanonicalBrowsingContext.cpp>`_
When a :cpp:class:`BrowsingContext` is constructed in the parent process,
it is actually an instance of :cpp:class:`CanonicalBrowsingContext`.
Due to being in the parent process, more information about the context is
available from a ``CanonicalBrowsingContext``.
.. cpp:class:: WindowContext
.. hlist::
:columns: 3
* `header (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/WindowContext.h>`_
* `source (searchfox) <https://searchfox.org/mozilla-central/source/docshell/base/WindowContext.cpp>`_
.. cpp:class:: WindowGlobalParent : public WindowContext, public WindowGlobalActor, public PWindowGlobalParent
.. hlist::
:columns: 3
* `source (searchfox) <https://searchfox.org/mozilla-central/source/dom/ipc/WindowGlobalParent.cpp>`_
.. cpp:class:: WindowGlobalChild : public WindowGlobalActor, public PWindowGlobalChild
.. hlist::
:columns: 3
* `source (searchfox) <https://searchfox.org/mozilla-central/source/dom/ipc/WindowGlobalChild.cpp>`_