Website performance is a hugely important topic, so much so that the big companies of the Web are obsessed with it. For the Googles, Yahoos, Amazons and eBays, slow websites mean fewer users and less happy users and thus lost revenue and reputation.
At PubCon, Matt Cutts from Google said there is strong lobbying in Google to introduce a new ranking factor into the algorithm. The new ranking factor has to do with how fast a site or page loads. Matt described this as one of his ‘what to expect in 2010′ bullet points in his presentation yesterday evening in Las Vegas.
- The script engine then looks at the content in the script block (which may have been delivered earlier), sighs, complains about the poor code, scratches its head and then does what the script tells it to do.
- Once the script engine is done, it reports back to the browser, which puts down its coffee, says good-bye to the script engine and looks at the rest of the document (which might have been changed, because the script may have altered the HTML).
- Yahoo’s Yslow
- Google’s Page Speed
- AOL’s WebPageTest
- Google的Sprite Me
YSlow is a Firebug add-on from Yahoo that allows you to automatically check your website for performance issues.
Like YSlow, Page Speed by Google is also an add-on for Firebug. Its main difference is that it does a lot of the optimization for you and provides the modified code and images immediately.
Rather late to the game, AOL’s WebPageTest is an application with some very neat features. (It is also available as a desktop application, in case you want to check Intranets or websites that require authentication.)
Sprite Me was produced by Google (under the supervision of Steve Souders) and allows you to create Sprites automatically from any website, even via a bookmarklet. It analyzes the images on a page and offers you various options before generating the Sprite and CSS for you.
Image Sprites were first discussed in an article published by Dave Shea and based on the work of Petr Stanicek.
在传统做法中，我们希望把网页上的图片切割的越讲究（指降低图片大小）越好，但这起到的效果是微乎其微的，甚至都感觉不到。CSS Sprites 从减少服务器发送请求出发，告诉我们要把许多图片整合为一张，这样会更有效率。同时造成延迟的可能性也就越小。
使用Network Distributed Hosting技术
If you use a library or CSS provided by a library, make sure to use the hosted versions of the files. In the case of YUI, this is done for you if you use the configurator. And you can pick from Yahoo or Google’s network.
For other libraries, there is a Google code repository of AJAX libraries. This is useful for a few reasons:
- There is a high probability that these servers are faster than yours.
- Visitors who have visited other websites that use the same includes will already have them on their computers and won’t need to load them again.
- You save on bandwidth and can easily upgrade the library by changing the version number of the include.