I did something similar with javascript. Sice I don't like to break the logics of a website if the user agent disabled javascript, there's a lot of code pollution to make things work if javascript is not enabled, but that's the price to pay:
I hope you can reuse some of the code below and adapt it to your needs, for example by using onkeydown() event handler and trigger a submitform(true) somehow:
the trick is to use display:none to hide javascript buttons if javascript is not enabled. It will only be changed on the fly to visible by javascript.