Pretty simple structure. You may notice anonchangehandler on theinput. We’ll take a look at that later. It would also be a good idea to add anactionto theformand asubmitbutton to help out those people who don’t have JavaScript enabled. Then you can use JavaScript to get rid of them...
Username checking:On the homepage of the chat, when you choose your username, jQuery is there watching that text input. When you type a character (on keyup) it asks a certain PHP file (via AJAX) if that username is in use. The PHP file responds with a yes or no, and a message is...