Javascript function in clientside events not working with firefox

[PH0ENIX]

I have a div with mouseover, mouseout, keypress and keyup events.\[code\]<div onkeydown="onkeydownClosePopUp('options0');" onkeypress="show_menu('options0');" onmouseout="hide_menu('options0');" onmouseover="show_menu('options0');" class="subHeadingPrincipleOptions"> <span class="sidelink"><a class="optionlink" href="http://stackoverflow.com/questions/9171458/#">options...</a></span><br> <table summary="" id="options0" class="principlesOptionsTable" style="visibility: hidden;"> <tbody> <tr> <td> <div class="principleoptionsmenu"> <ul class="principleoptions"> <li><a class="sidelink" href="http://stackoverflow.com/questions/9171458/Policies4principle.aspx?PolSet=Pol1&Principle=2&tab=lk"> rules...</a><br> </li> <li><a class="sidelink" onclick="window.open('feedback.aspx?PolSet=Pol1&Principle=2','newwindow','width=500,height=600,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,copyhistory=yes,resizable=yes');return false" title="open in new window" href="http://stackoverflow.com/questions/9171458/feedback.aspx?polset=Pol1&Principle=2">feedback...</a></li></ul> </div> </td> </tr> </tbody> </table> </div>\[/code\]The script tag is \[code\]<script type="text/javascript"> function show_menu(m) { if(event.keyCode!=27) { var myElement =document.getElementById(m); myElement.style.visibility="visible"; } } function hide_menu(m) { var myElement =document.getElementById(m); myElement.style.visibility="hidden"; } function onkeydownClosePopUp(m) { if(event.keyCode==27) { var myElement =document.getElementById(m); myElement.style.visibility="hidden"; } }\[/code\]This perfectly working in all browsers except firefox. Whats change is to be need to make this work with firefox?