YSlow

YSlow analyzes web pages and suggests ways to improve their performance based on the following set of rules for high performance web pages:

* Minimize HTTP Requests
* Use a Content Delivery Network
* Avoid empty src or href
* Add an Expires or a Cache-Control Header
* Gzip Components
* Put StyleSheets at the Top
* Put Scripts at the Bottom
* Avoid CSS Expressions
* Make JavaScript and CSS External
* Reduce DNS Lookups
* Minify JavaScript and CSS
* Avoid Redirects
* Remove Duplicate Scripts
* Configure ETags
* Make AJAX Cacheable
* Use GET for AJAX Requests
* Reduce the Number of DOM Elements
* No 404s
* Reduce Cookie Size
* Use Cookie-Free Domains for Components
* Avoid Filters
* Do Not Scale Images in HTML
* Make favicon.ico Small and Cacheable