Measure Page Load Time

PageSpeed Service was turned off on August 3rd, 2015. Please see Turndown Information for PageSpeed Service.

Objective

Measure Page Load Time for all your HTML pages.

Description

This rewriter injects two small blocks of CSI (Client Side Instrumentation) javascript into every HTML page. These blocks measure the time the client spends loading and rendering the page, and report that measurement back to the server. You can access the average page load time metrics for your site on the Dashboard pane of the Google APIs Console.

This rewriter is enabled by default for all pages served by PageSpeed Service, and is disabled only for pages blacklisted in the Rewriter Settings pane of the Google APIs Console.

Operation

This rewriter injects CSI javascript blocks into the head tag and at the end of the HTML page and causes requests of the form http://www-accel-pss.googleusercontent.com/csi?rt=ol.200 to be sent to the PageSpeed Service for recording the Page Load Time for the page.

Example

The example below shows the HTML before rewriting: 

<html>
  <body>
    Hello World
  </body>
</html>

and after rewriting: 

<html>
  <head>
    <script> function(){function.....   }(); </script>
  </head>
  <body>
    Hello World
    <script>function(){if(window.pss_jstiming ........
      window.addEventListener('load', f, false);  }}) ();
    </script>
  </body>
</html>