YSlow analyzes web pages and tells you why they're slow based on Yahoo's
rules for high performance web sites.

YSlow gives you:
* Performance report card
* HTTP/HTML summary
* List of components in the page
* Tools including JSLint

Most files comprising YSlow are licensed under the Mozilla Public License
(MPL) version 1.1, with a couple of exceptions. YSlow includes jslint by
Douglas Crockford, which is licensed under a BSD-style license. YSlow also
includes files from the Yahoo! User Interface library, which are licensed
under the BSD license.

WWW: http://developer.yahoo.com/yslow/