Which web designing software can be used to design a site like mega.co.nz

[zemane]

I'm just wondering about the design of mega.co.nz website. Mainly its Ajax based site but I have no idea using which web designing software mage.co.nz is made of.Is it possible do all the css,javascript, php, ajax designing using one web designing software?I heard that they are going to launch a site for music called megabox , I found the video of making that site on youtube, its just like mega.co.nz.Any idea?Thanks