Front-end development tools

Fiddler
A powerful HTTP stream viewing tool
Http://www.fiddlertool.com/fiddler/

Httpwatch
Data analysis tools, view of accept/send headers, and view post data.
Http://www.httpwatch.com

IE developer toolsbar
Firebug. html and CSS debugging tools in IE
Http://www.windowsmarketplace.com/details.aspx? Itemid = 2695980.

Companion. js
Javascript debugging tools under ie. Good news! Good news !! Good news !!!
Http://www.my-debugbar.com/wiki/CompanioNJS/HomePage

Firebug
God-like plug-ins

Web Developer
The viewing tool in Firefox allows you to view JS, CSS, and other page information.

Yslow
Page performance optimization viewer. Based on firebug
Http://developer.yahoo.com/yslow

Javascript Debugger
The javascript debugging tool in Firefox has more powerful debugging functions than firebug.

Opera Developer Tools
Dom and CSS viewing tools under opera, similar to firebug.
Http://dev.opera.com/articles/view/opera-developer-tools/

WebKit
Development and debugging tools under Safari
Http://nightly.webkit.org/