browsingContext.contextCreated event

Event data

The params field in the event notification is a context object with the following properties:

children

An array of context objects that represents child contexts. This event does not include child contexts (maxDepth is 0). To retrieve the children of a context, use browsingContext.getTree.

clientWindow

A string that contains the ID of the client window that contains this context.

context

A string that contains the ID of the newly created context.

originalOpener

A string that contains the ID of the context that originally opened this context. The value is null if the context was opened directly (not by another context).

parent

A string that contains the ID of the parent context. The value is null if the context has no parent (that is, it is a top-level context).

url

A string that contains the URL of the context, including the fragment, at the time it was created. For newly created contexts, the value is "about:blank" because the event fires before any navigation has occurred and content has loaded. For existing contexts at subscription time, the value reflects their current URL.

userContext

A string that contains the ID of the user context associated with this context.

Description

When you subscribe to this event, the browser immediately fires the event recursively for all contexts that already exist at the time of subscription, starting from top-level contexts down through their children.

If the subscription was scoped to specific contexts using the contexts parameter, only child contexts created within those contexts will fire the event.

Examples

Receiving an event for a new tab

Assume you have a WebDriver BiDi connection, an active session, and a subscription to browsingContext.contextCreated active.

When your automation script creates a tab using browsingContext.create, the browser sends the following notification:

{
  "type": "event",
  "method": "browsingContext.contextCreated",
  "params": {
    "context": "93ee5bd6-d256-4608-a002-9a8995cc0e5f",
    "children": null,
    "originalOpener": null,
    "url": "about:blank",
    "userContext": "default",
    "clientWindow": "08c697a1-2664-447d-9c88-52bcee3bb386",
    "parent": null
  }
}

Receiving an event for a child context

Assume you have a WebDriver BiDi connection, an active session, and a subscription to browsingContext.contextCreated active.

Suppose a page containing an <iframe> loads. The browser sends the following notification for the new child context:

{
  "type": "event",
  "method": "browsingContext.contextCreated",
  "params": {
    "context": "6442450945",
    "children": null,
    "originalOpener": null,
    "url": "about:blank",
    "userContext": "default",
    "clientWindow": "08c697a1-2664-447d-9c88-52bcee3bb386",
    "parent": "93ee5bd6-d256-4608-a002-9a8995cc0e5f"
  }
}

Identifying the opener of a context

Assume you have a WebDriver BiDi connection and an active session.

Consider a scenario where two tabs are already open: Tab 1 at https://example.com/page1.html, and Tab 2 at https://example.com/page2.html, which was opened from Tab 1 using window.open(). When you subscribe to browsingContext.contextCreated, the browser fires events for the two existing contexts. The originalOpener field in Tab 2's notification identifies the context that opened it.

The browser sends the following notification for Tab 1:

{
  "type": "event",
  "method": "browsingContext.contextCreated",
  "params": {
    "context": "93ee5bd6-d256-4608-a002-9a8995cc0e5f",
    "children": null,
    "originalOpener": null,
    "url": "https://example.com/page1.html",
    "userContext": "default",
    "clientWindow": "08c697a1-2664-447d-9c88-52bcee3bb386",
    "parent": null
  }
}

This is immediately followed by the notification for Tab 2:

{
  "type": "event",
  "method": "browsingContext.contextCreated",
  "params": {
    "context": "32ed30da-24ad-459d-8f0d-660526e92d96",
    "children": null,
    "originalOpener": "93ee5bd6-d256-4608-a002-9a8995cc0e5f",
    "url": "https://example.com/page2.html",
    "userContext": "default",
    "clientWindow": "08c697a1-2664-447d-9c88-52bcee3bb386",
    "parent": null
  }
}

Specifications

Browser compatibility

See also

• browsingContext.contextDestroyed event
• browsingContext.create command
• browsingContext.getTree command
• session.subscribe command