What's the most common language used in web dev?

HTML, CSS, and Javascript in first place :).
Whatever programming language that you use (PHP, ASP.Net, Java, etc...), core of web development start with these 3.
PHP and ASP.net keep fighting from years to take the lead on web development.

I've read a lot about this, most of the articles i read says it's PHP, i think i agree on that but here is an interesting article about 10 web languages you should know about http://www.eweek.com/c/a/IT-Management/10-Programming-Languages-You-Should-Learn-Right-Now/

It all depends on the market.
In Jordan the most common used language is ASP.NET but world wide it's PHP.
The main reason is because PHP works on any platform and specially on FREE linux, while ASP.NET requires a purchased Windows, along with other reasons.
If you look at the most visited websites you will find that most of them are written in PHP such as Facebook and Wikipedia, and believe me these huge companies didn't select PHP before they did their homework.
One last thing: Don't relay on articles as the writer might be bias towards the language he knows best.

i don't like php , i think asp.net better that's why i see all the web as asp product maybe php is more widespread

i think it's PHP ...
but i like ASP :)

i read about it , its php for sure

HTML, PHP and JQuery and some times ASP.Net and Ajax

Its Absoultly PHP some of java , asp.net

First Of all The are to type of programming language ( server side  - client side)

 

Clinet Side

 

1- HTML, stylesheet ( CSS ,LESS ,sass ), script ( Javascript , coffee script)

 

Server Side

 

1 - PHP

2- Ruby on RaILS

3- ASP.NET MVC

4- Node.js

PHP of course

My vote is for PHP at1st rank.

then ASP.NET

then ROR is taking more space nowadays.