There are lot's of applications for web design. In this artical, I'll explain some Popular tools for web design.

1. Firebug

Firebug is a free, open source in-browser web development tool for the Firefox web browser. It’s many features include: on-the-fly HTML and CSS editing for tweaking or debugging, a Console for logging, analyzing and debugging JavaScript, and an intuitive Document Object Model (DOM) inspection tool to help you quickly see how the elements of a web page relates to one another.
Firebug’s popularity is so immense it’s one of the few Firefox extensions that have its own extensions (like YSlow and FirePHP)!

2. Photoshop

 Adobe Photoshop is a very popular commercial graphics editor available for the Mac and Windows operating system.