tab page javascript operation

I have a div which contains dhtmlxmenu, dhtmlxtoolbar and a dhtmlxtabbar. I dynmically load the tabbar and its content via menu options. In the tabbar content I have a form (standard html) in which I need to detect onkeydown as I have popup windows that needs to be displayed when certain function keys are pressed.
I had read somewhere in the documentation that we cannot run javascript in the loaded html, but I (possibly erroneously) assumed that would be chunks of javascript rather than a defined call on the input box.
Am I correct in now thinking that I cannot declare javascript events on an input box loaded this way?
If so would it be possible to add an event to the input box after the page is loaded?
Your help would be appreciated.

All sorted - asked for help prematurely

JS that is loaded with content via Ajax (setContentHref method) is executed. If the problem is not solved, please attach the complete demo. We need it to reproduce your issue and make any conclusions on your question. … leted_demo