O'Reilly logo

Responsive Media in HTML5 by Alex Libby

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Using tools to determine speed

There are plenty of ways to determine if our site is running slowly—arguably one of the most well known is YSlow by Yahoo available at https://developer.yahoo.com/yslow/. In the following screenshot, it is shown in use from within Firebug:

Using tools to determine speed

YSlow is perfect to establish where there are slow elements in our pages. It uses a number of rules based on research by Yahoo's Exceptional Performance Team to work out how well a site measures up against its standards for performance.

Let's take a look at using it to see if some well-known sites could be improved. As an example, we'll begin with installing YSlow as a plugin for ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required