I am designing a HTML page. In that page there is  a horizontal menu with dropdown menu items.
but on Google Chrome, this menu bar is working fine. But on Internet Explorer and Firefox, it is not displaying accordingly.
So, i want to know what code should i have to be added to make it platform independent menu bar.
<link href="css/style.css" rel="stylesheet" type="text/css" />
<style type="text/css">
/*---- CROSS BROWSER DROPDOWN MENU ----*/
 ul#nav {
   margin: 0 0 0 0px;}
 ul.drop a {
   display:block; color: #fff; font-family: Bodoni MT; font-size: 19px; text-decoration: none;}
 ul.drop, ul.drop li, ul.drop ul {
   list-style: none; margin: 0; padding: 0; border: 1px solid #fff; background: #888; color: #fff;}
 ul.drop {
   position: relative; z-index: 597; float: left; width:100%;
        top: 0px;
        left: 0px;
        height: 33px;
    }
 ul.drop li {
   float: left; line-height: 1.3em; vertical-align: middle; zoom: 1; padding: 5px 10px; }
 ul.drop li.hover, ul.drop li:hover {
   position: relative; z-index: 599; cursor: default; background: #1e7c9a; }
 ul.drop ul {
   visibility: hidden; position: absolute; top: 100%; left: 0; z-index: 598; width: 155px; /* 245px; */
   background: #888; border: 1px solid #fff; }
 ul.drop ul li {
   float: none; }
 ul.drop ul ul {
   top: -2px; left: 100%; }
 ul.drop li:hover > ul {
   visibility: visible }
/* This rule will be applied to hide element on the page */
 .hidden { display: none; }
 #toggled_0 { height:100px; width:300px; border:1px solid  blue; overflow:auto; }
</style>
<!-- <script type="text/javascript" src="MenuCommon.js"></script> -->
<script type="text/javascript">
    /*---- CROSS BROWSER DROPDOWN MENU ----*/
    // Checks that the class 'className' is defined for the element 'el'
    function hasClass(el, className) {
        var re = new RegExp('(?:^|\\s+)' + className + '(?:\\s+|$)', 'g');
        return re.test(el.className);
    }
    // Adds the class 'className' to the element 'el'
    function addClass(el, className) {
        if (!hasClass(el, className)) {
            el.className += ' ' + className;
        }
    }
    // removes the class 'className' from the element 'el'
    function delClass(el, className) {
        var re = new RegExp('(?:^|\\s+)' + className + '(?:\\s+|$)', 'g');
        el.className = el.className.replace(re, ' ');
    }
    // Toggles the class 'className' to the element 'el'
    function toggleClass(el, className) {
        if (hasClass(el, className)) { delClass(el, className); }
        else {
            addClass(el, className);
        }
    }
</script>
</head>
<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="0">
      <tr style="background-image: url(img/topbg.jpg);">
        <td> </td>
        <td valign="top"><table width="990" border="0" align="center" cellpadding="0" cellspacing="0">
          <tr>
            <td valign="top"><table width="990" border="0" cellspacing="0" cellpadding="0">
              <tr>
                <td width="102" valign="middle"><img src="img/logo1.jpg" width="102" height="155"/></td>
                <td width="888" valign="top"><table width="888" border="0" cellspacing="0" cellpadding="0">
                  <tr>
                    <td><table width="888" border="0" cellspacing="0" cellpadding="0">
                      <tr>
                        <td width="521"> </td>
                        <td width="367"><table width="367" border="0" align="right" cellpadding="0" cellspacing="0">
                          <tr>
                            <td></td>
                          </tr>
                         
                          <tr>                          </tr>
                        </table></td>
                      </tr>
                    </table></td>
                  </tr>
                  <tr>
                    <td> </td>
                  </tr>
                  <tr>
                    <td><table width="888" border="0" cellspacing="0" cellpadding="0">
                      <tr>
                        <td width="803"><img src="img/ccstext1.png" width="803" height="87" /></td>
                        <td width="85"><img src="img/logo2.jpg" width="85" height="87" /></td>
                      </tr>
                    </table></td>
                  </tr>
                  <tr>
                    <td class="consu"><div align="right"></div></td>
                  </tr>
                </table></td>
              </tr>
            </table></td>
          </tr>
          <tr>
            <td >
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Thanks in advance.