OT-Javascript Question

Hi everyone, I know this is off topic, but I was hoping someone could explain this to me. It may be something with php, not sure though. I have this exact code on a regular html file and it works fine, copy paste to php file, and it doesn't work. <script language="JavaScript" src="handler.js"></script> *snip* <input type="text" name="10_Accounting_Unit" size="1" maxlength="1" value="{$_SESSION['10_Accounting_Unit']}" onKeyUp="movefocus(10_Accounting_Unit,11_Accounting_Unit,1);"> and the movefocus function is basically just if 10_Accounting_Unit.length == 1 11_Accounting_Unit.focus; of course it's a function, and the variables are used.. etc.. but I was just wondering why this doesn't work on my php page. Thanks, Jake