Are you talking about a chat box similar to what Facebook uses? You can build a simple chat box with PHP, this involves more programming opposed to "design". To create the site, you'd have to learn HTML along with CSS. HTML for structuring things like headings, text, etc. CSS is then used format those things such as: adding color, adjusting placement, etc.

Next JavaScript is used to add interaction, and store minimal data of users. You can do things like pop up messages, or stop pages for advancing if a email isn't provided.

After all that, PHP is used for heavy duty server side functionality. To keep it simple, PHP is a full blown programming language that will take time to learn. It's almost like HTML and JavaScript put together in one, but can it can do far more. In no way do I mean you can replace HTML and JavaScript completely with PHP. Basically, when you hear the term web programming, think of PHP. When you hear web development, think HTML & CSS. JavaScript can sorta go in either.

Thanks for that mate ! I know a good deal of HTML and the basic CSS but do you know any good websites for learning Javascript and PHP ?

Team TreeHouse or possibly code academy. I'd recommend reading though . If you're not familiar with some of the basics of coding, it can be really tricky. Oreilly publishing has quite a bit of books con JavaScript, and a few on PHP. If you don't want to learn the code you could just use jQuery, which is a library of prewritten JavaScript code.

Edit: [ Register or Signin to view external links. ] is a good place to start for JavaScript.