If I have understood your question correctly you are using AJAX to submit a request for login .

Use type = post instead of GET in the call it will resolve your problem.

There are special steps you probably need to take: certain response headers are usually set that hint to the client browser to not cache the page. I don't recall what they all are, except that code I've seen at the workplace has three separate headers all being set. (IE needs one or two different from FF, for one thing.) Not *much* to go on, but you want to look at / google for "response headers". Once that's done, you probably want to forcefully dump your browser's cache (FF2 - Tools > Clear Private Data...) before you try it, as it'll of course still be cached otherwise. (Then for good measure, *also* restart the browser.)