BrowserContexts provide a way to operate multiple independent browser sessions.
If a page opens another page, e.g. with a `window.open` call, the popup will belong to the parent page's browser context.
Playwright allows creation of "incognito" browser contexts with `browser.newContext()` method. "Incognito" browser contexts don't write any browsing data to disk.
The event is emitted when a new Page is created in the BrowserContext. The page may still be loading. The event will also fire for popup pages. See also [page.on('popup')](api/class-page.md#pageonpopup) to receive events about popups relevant to a specific page.
The earliest moment that page is available is when it has navigated to the initial url. For example, when opening a popup with `window.open('http://example.com')`, this event will fire when the network request to "http://example.com" is done and its response has started loading in the popup.
> **NOTE** Use [page.waitForLoadState([state, options])](api/class-page.md#pagewaitforloadstatestate-options) to wait until the page gets to a particular state (you should not need it in most cases).
-`url`<[string]> either url or domain / path are required. Optional.
-`domain`<[string]> either url or domain / path are required Optional.
-`path`<[string]> either url or domain / path are required Optional.
-`expires`<[number]> Unix time in seconds. Optional.
-`httpOnly`<[boolean]> Optional.
-`secure`<[boolean]> Optional.
-`sameSite`<"Strict"|"Lax"|"None"> Optional.
- returns: <[Promise]>
Adds cookies into this browser context. All pages within this context will have these cookies installed. Cookies can be obtained via [browserContext.cookies([urls])](api/class-browsercontext.md#browsercontextcookiesurls).
-`content`<[string]> Raw script content. Optional.
-`arg`<[Serializable]> Optional argument to pass to `script` (only supported when passing a function).
- returns: <[Promise]>
Adds a script which would be evaluated in one of the following scenarios:
* Whenever a page is created in the browser context or is navigated.
* Whenever a child frame is attached or navigated in any page in the browser context. In this case, the script is evaluated in the context of the newly attached frame.
The script is evaluated after the document was created but before any of its scripts were run. This is useful to amend the JavaScript environment, e.g. to seed `Math.random`.
An example of overriding `Math.random` before the page loads:
```js
// preload.js
Math.random = () => 42;
```
```js
// In your playwright script, assuming the preload.js file is in same directory.
await browserContext.addInitScript({
path: 'preload.js'
});
```
> **NOTE** The order of evaluation of multiple scripts installed via [browserContext.addInitScript(script[, arg])](api/class-browsercontext.md#browsercontextaddinitscriptscript-arg) and [page.addInitScript(script[, arg])](api/class-page.md#pageaddinitscriptscript-arg) is not defined.
-`handle`<[boolean]> Whether to pass the argument as a handle, instead of passing by value. When passing a handle, only one argument is supported. When passing by value, multiple arguments are supported.
The method adds a function called `name` on the `window` object of every frame in every page in the context. When called, the function executes `callback` and returns a [Promise] which resolves to the return value of `callback`. If the `callback` returns a [Promise], it will be awaited.
The method adds a function called `name` on the `window` object of every frame in every page in the context. When called, the function executes `callback` and returns a [Promise] which resolves to the return value of `callback`.
Returns all open pages in the context. Non visible pages, such as `"background_page"`, will not be listed here. You can find them using [chromiumBrowserContext.backgroundPages()](api/class-chromiumbrowsercontext.md#chromiumbrowsercontextbackgroundpages).
-`url`<[string]|[RegExp]|[function]\([URL]\):[boolean]> A glob pattern, regex pattern or predicate receiving [URL] to match while routing.
-`handler`<[function]\([Route], [Request]\)> handler function to route the request.
- returns: <[Promise]>
Routing provides the capability to modify network requests that are made by any page in the browser context. Once route is enabled, every request matching the url pattern will stall unless it's continued, fulfilled or aborted.
An example of a naïve handler that aborts all image requests:
Page routes (set up with [page.route(url, handler)](api/class-page.md#pagerouteurl-handler)) take precedence over browser context routes when request matches both handlers.
> **NOTE** [page.setDefaultNavigationTimeout(timeout)](api/class-page.md#pagesetdefaultnavigationtimeouttimeout) and [page.setDefaultTimeout(timeout)](api/class-page.md#pagesetdefaulttimeouttimeout) take priority over [browserContext.setDefaultNavigationTimeout(timeout)](api/class-browsercontext.md#browsercontextsetdefaultnavigationtimeouttimeout).
This setting will change the default maximum time for all the methods accepting `timeout` option.
> **NOTE** [page.setDefaultNavigationTimeout(timeout)](api/class-page.md#pagesetdefaultnavigationtimeouttimeout), [page.setDefaultTimeout(timeout)](api/class-page.md#pagesetdefaulttimeouttimeout) and [browserContext.setDefaultNavigationTimeout(timeout)](api/class-browsercontext.md#browsercontextsetdefaultnavigationtimeouttimeout) take priority over [browserContext.setDefaultTimeout(timeout)](api/class-browsercontext.md#browsercontextsetdefaulttimeouttimeout).
-`headers`<[Object]<[string], [string]>> An object containing additional HTTP headers to be sent with every request. All header values must be strings.
- returns: <[Promise]>
The extra HTTP headers will be sent with every request initiated by any page in the context. These headers are merged with page-specific extra HTTP headers set with [page.setExtraHTTPHeaders(headers)](api/class-page.md#pagesetextrahttpheadersheaders). If page overrides a particular header, page-specific header value will be used instead of the browser context header value.
> **NOTE** `browserContext.setExtraHTTPHeaders` does not guarantee the order of headers in the outgoing requests.
> **NOTE** Consider using [browserContext.grantPermissions(permissions[, options])](api/class-browsercontext.md#browsercontextgrantpermissionspermissions-options) to grant permissions for the browser context pages to read its geolocation.
Provide credentials for [HTTP authentication](https://developer.mozilla.org/en-US/docs/Web/HTTP/Authentication).
> **NOTE** Browsers may cache credentials after successful authentication. Passing different credentials or passing `null` to disable authentication will be unreliable. To remove or replace credentials, create a new browser context instead.
-`path`<[path]> The file path to save the storage state to. If `path` is a relative path, then it is resolved relative to [current working directory](https://nodejs.org/api/process.html#process_process_cwd). If no path is provided, storage state is still returned, but won't be saved to the disk.
-`url`<[string]|[RegExp]|[function]\([URL]\):[boolean]> A glob pattern, regex pattern or predicate receiving [URL] used to register a routing with [browserContext.route(url, handler)](api/class-browsercontext.md#browsercontextrouteurl-handler).
-`handler`<[function]\([Route], [Request]\)> Optional handler function used to register a routing with [browserContext.route(url, handler)](api/class-browsercontext.md#browsercontextrouteurl-handler).
- returns: <[Promise]>
Removes a route created with [browserContext.route(url, handler)](api/class-browsercontext.md#browsercontextrouteurl-handler). When `handler` is not specified, removes all routes for the `url`.
-`event`<[string]> Event name, same one would pass into `browserContext.on(event)`.
-`optionsOrPredicate`<[Function]|[Object]> Either a predicate that receives an event or an options object. Optional.
-`predicate`<[Function]> receives the event data and resolves to truthy value when the waiting should resolve.
-`timeout`<[number]> maximum time to wait for in milliseconds. Defaults to `30000` (30 seconds). Pass `0` to disable timeout. The default value can be changed by using the [browserContext.setDefaultTimeout(timeout)](api/class-browsercontext.md#browsercontextsetdefaulttimeouttimeout).
- returns: <[Promise]<[Object]>>
Waits for event to fire and passes its value into the predicate function. Returns when the predicate returns truthy value. Will throw an error if the context closes before the event is fired. Returns the event data value.
