CODEIGNITER ROOKIE

[eluser]djjonex[/eluser]
Hello everyone, I'm trying to make a register form and I would like to check if the username is available... I know thats AJAX... I know that I can create a button that calls a javascript function.... the script read the input, send to the PHP code(db query), and receive the answer to display in a <div>....

The thing I don't know is how to do it in CodeIgniter .... If somebody wants to help me with the sintax or give me some examples ... I'll appreciate...

Thank!