Tuesday, August 2, 2011

Page Performance Optimization Methods

There has been a great deal of interest in the web community recently about how to speed up web page delivery. At least some of this discussion is prompted by the increasing sizes of web pages, particularly for AJAX and Web 2.0 applications. For example, a few years ago a 100 KByte page would be considered "large," but now we see some pages that download 1 MByte, and these are considered "normal". Some website, e.g. the CNN site, regularly download 1.5-2.5 MBytes -- and that's not counting videos. In earlier times web page component counts could be in the low tens, now the component counts are 100+. On a recent day, CNN's page had 113 individual URLs involved.

To improve average download performance you have to buy your customers more bandwidth (this could be expensive!), or you need to figure out how to reduce the size of your pages (tedious, but very effective). But to fix something you have to understand it, and that's where a couple of eValid tricks come into play.

Page Metrics Popup

This is an eValid feature that runs along with your browsing activity.

As you navigate through a website, after each page is fully downloaded you see a simple popup like the one at the right (click on the image to see the full picture).

The data extracted by eValid includes the size of the base page, the total number of URLs involved, and all of the details about the internal structure of the page including the total size of the download.

Here are the details on eValid's Page Metrics Popup feature.

PageSpeed Process

The eValid PageSpeed Process uses the "detailed page timings" feature to collect page component byte-count and download times, in the order in which each component is recovered and rendered.

The resulting "stack chart" reveals detailed the download time and size of each page component, by simply hovering your mouse over the display bars. This way, you know which element is the bottleneck.

Bottom Line: eValid gives you all the details on what's what about your page. It's up to you to fix the problems eValid analytics reveals. That's a lot easier to do if you know what's wrong.

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