Display Menu List on IE9

This is a much simplified version of your code with the benefit of working in IE9 as well as FF and Chrome.
You can continue to modify the CSS to change colors, positions, widths, etc., but it could be a re-start for your needs.

Code:

<!DOCTYPE html> <html lang="en"> <meta charset="utf-8" /> <title> Simple Menu </title> <style type="text/css"> .hide { display:none; } .show { display:block; width:200px; border:1px solid black; } a { text-decoration:none; } .menuLI { display:block; float:left; width:70px; } #menu li { list-style-type:none; cursor:pointer; } #menu li:hover { background-color:orange; } #menu div li { list-style-type:none; display:block; clear:both; } #menu div li:hover { background-color:orange; } #Forums div { display:none } #NSU div { display:none; } #Email div { display:none;} </style> </head> <body> <ul id="menu"> <li onclick="showHide('Forums',this,0)" class="menuLI">Forums</li> <li onclick="showHide('NSU',this,1)" class="menuLI">NSU</li> <li onclick="showHide('Email',this,2)" class="menuLI">Email</li> <br style="clear:both" /> <div id="Forums" class="hide"> <li> <a href="http://www.webdeveloper.com">Webdeveloper</a></li> <li> <a href="http://www.codingforums.com">Coding Forums</a></li> <li> <a href="http://www.dreamincode.net">Dream-In-Code</a></li> </div> <div id="NSU" class="hide"> <li> University </li> <li> HPD </li> <li> Optometry </li> <li> Library </li> </div> <div id="Email" class="hide"> <li> Exchange </li> <li> Gmail </li> <li> Bellsouth </li> </div> </ul> <script type="text/javascript"> function showHide(IDS,curLI,wide) { var sel = document.getElementById('menu').getElementsByTagName('div'); var lis = document.getElementById('menu').getElementsByTagName('li'); for (var i=0; i<sel.length; i++) { if (sel[i].id != IDS) { sel[i].className = 'hide'; } lis[i].style.backgroundColor = "transparent"; } sel = document.getElementById(IDS); sel.style.marginLeft = (wide*70)+'px'; // needs to match width value of .menuLI in style section if ( sel.className == "hide" ) { sel.className = 'show'; curLI.style.backgroundColor = "orange"; } else { sel.className = 'hide'; curLI.style.backgroundColor = "transparent"; } } </script> </body> </html>

If of no use to you, then just ignore the post.

BTW, it is a good idea to put your script between [ code] and [ /code] tags (without the spaces)
to make it easier to read your code as well as retain the formatting structure.