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# JavascriptContextHandler (interface)
Implement this interface to handle javascript exceptions globally.
For an example of how to implement handler see [cefpython](cefpython.md).CreateBrowser(). For a list of all handler interfaces see [API > Client handlers](API#Client_handlers).
Table of contents:
* [Callbacks](#callbacks)
* [OnContextCreated](#oncontextcreated)
* [OnContextReleased](#oncontextreleased)
## Callbacks
### OnContextCreated
| Parameter | Type |
| --- | --- |
| browser | [Browser](Browser.md) |
| frame | [Frame](Frame.md) |
| __Return__ | void |
Called shortly after (process message delay) the V8 context for a frame has been created.
If the page does not contain `