The easiest way to profile web pages is by using the Blackfire Companion for Firefox. The Companion lets you profile the current web page displayed in your browser in a click.
Install the Blackfire Companion from the Mozilla Add-On website: https://addons.mozilla.org/firefox/addon/blackfire/
To profile web pages:
The Companion is not able to profile 304 HTTP responses as some Web Servers remove custom headers such as the ones added by Blackfire to operate correctly. So, to avoid 304 HTTP responses, the Companion removes any conditional headers from requests; if you want to profile 304 responses, use the Blackfire cURL CLI command instead.
The Firefox extension is automatically updated by the Firefox Scheduler.