How to make Remote Function work in codeigniter framework?

[eluser]garymardell[/eluser]
Turn the ajax request into a POST request rather than a GET one.

And then use $this->input->post('username'); to get the value.

I think your current problem is that you don't have query strings enabled and you haven't set the right URI_PROTOCOL in your config file. Some of them don't work on certain servers, if you go through them all and refresh the page (directly accessing the url) then you should find one that works. However it is probably easier to change it to a post request and the value will be escaped for you as well.