# Firefox

Using a Web Browser is the easiest way to [profile web applications](../../profiling-cookbooks/profiling-http-via-browser). Blackfire supports Firefox and [Google Chrome](chrome).

## Installing the Firefox Extension

## Upgrading the Extension

The Firefox extension is automatically updated by the Firefox Scheduler.

## Content Security Policy

The browser extension injects a toolbar in the profiled webpage and uses an `<iframe>` to communicate with the probe.

In case the web page declares a [Content Security Policy](https://en.wikipedia.org/wiki/Content_Security_Policy) regarding frames usages, the communication may be broken and you would be informed in the toolbar.

In this case, you can declare Blackfire domain as trusted by adding the `blackfire.io` domain in your application's headers:

```text
Content-Security-Policy: frame-src 'self' blackfire.io
```