CSS - Drop Down Menu Positioning Issue

<!--	  START OF MENU	  !-->

<table width='730' height='30'>
<tr>
	
	
	<td width='20%' align='center'>
	<div id='menu1a'>
	<a href='#'>Menu 1</a>
	</div>
	<div id='menu1b' class='menu_dropdown'>
	<table width='150' height='50'>
	<tr>
		<td class='padded'>
		<table width='100%' height='100%'>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu1_1a'>
			<a href='#'>Item 1</a>
			</div>
			</td>
		</tr>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu1_2a'>
			<a href='#'>Item 2</a>
			</div>
			</td>
		</tr>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu1_3a'>
			<a href='#'>Item 3</a>
			</div>
			</td>
		</tr>
		</table>
		</td>
	</tr>
	</table>
	</div>
	<script type='text/javascript'>at_attach('menu1a', 'menu1b', 'hover', 'y', 'pointer');</script>
	</td>
	
	
	<td width='20%' align='center'><div id='menu2a'>
	<a href='#'>Menu 2</a>
	</div>
	<div id='menu2b' class='menu_dropdown'>
	<table width='150' height='50'>
	<tr>
		<td class='padded'>
		<table width='100%' height='100%'>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu2_1a'>
			<a href='#'>Item 2</a>
			</div>
			</td>
		</tr>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu2_2a'>
			<a href='#'>Item 2</a>
			</div>
			</td>
		</tr>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu2_3a'>
			<a href='#'>Item 3</a>
			</div>
			</td>
		</tr>
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu2_4a'>
			<a href='#'>Item 4   ></a>
			</div>
			
			<div id='submenu2_4b' class='menu_dropdown'>
			<table width='150' height='50'>
			<tr>
				<td class='padded'>
				<table width='100%' height='100%'>
				<tr>
					<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
					<a href='#'>Item 4a</a>
					</td>
				</tr>
				<tr>
					<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
					<a href='#'>Item 4b</a>
					</td>
				</tr>
				</table>
				</td>
			</tr>
			</table>
			</div>
			<script type='text/javascript'>at_attach('submenu2_4a', 'submenu2_4b', 'hover', 'y', 'pointer');</script>
			
			</td>
		</tr>					
		<tr>
			<td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'>
			<div id='submenu2_5a'>
			<a href='#'>Item 5</a>
			</div>
			</td>
		</tr>
		</table>
		</td>
	</tr>
	</table>
	</div>
	<script type='text/javascript'>at_attach('menu2a', 'menu2b', 'hover', 'y', 'pointer');</script></td><td width='20%' align='center'><div id='menu3a'><a href='#'>Menu 3</a></div><div id='menu3b' class='menu_dropdown'><table width='150' height='50'><tr><td class='padded'><table width='100%' height='100%'><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu3_1a'><a href='#'>Item 3</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu3_2a'><a href='#'>Item 2</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu3_3a'><a href='#'>Item 3</a></div></td></tr></table></td></tr></table></div><script type='text/javascript'>at_attach('menu3a', 'menu3b', 'hover', 'y', 'pointer');</script></td><td width='20%' align='center'><div id='menu4a'><a href='#'>Menu 4</a></div><div id='menu4b' class='menu_dropdown'><table width='150' height='50'><tr><td class='padded'><table width='100%' height='100%'><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu4_1a'><a href='#'>Item 4</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu4_2a'><a href='#'>Item 2</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu4_3a'><a href='#'>Item 3</a></div></td></tr></table></td></tr></table></div><script type='text/javascript'>at_attach('menu4a', 'menu4b', 'hover', 'y', 'pointer');</script></td><td width='20%' align='center'><div id='menu5a'><a href='#'>Menu 5</a></div><div id='menu5b' class='menu_dropdown'><table width='150' height='50'><tr><td class='padded'><table width='100%' height='100%'><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu5_1a'><a href='#'>Item 1</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu5_2a'><a href='#'>Item 2</a></div></td></tr><tr><td  class='menuNormal' onmouseover='expand(this);' onmouseout='collapse(this);'><div id='submenu5_3a'><a href='#'>Item 3</a></div></td></tr></table></td></tr></table></div><script type='text/javascript'>at_attach('menu5a', 'menu5b', 'hover', 'y', 'pointer');</script></td>				
	
</tr>
</table>

.menu_dropdown { background-color: #a5caad; border: 1px solid #057c1f; position: absolute; visibility: hidden; font-size: small; }
.menu_dropdown A:link {text-decoration: none; color: #000; font-weight: normal; }
.menu_dropdown A:visited {text-decoration: none; color: #000; font-weight: normal; }
.menu_dropdown A:active {text-decoration: none; color: #000; font-weight: normal; }
.menu_dropdown A:hover {text-decoration: underline; color: #000; font-weight: normal; }

td.menuNormal
{padding: 0px;
font-weight: bold;
vertical-align: top;
background-color:#a5caad;}

td.menuHover
{padding: 0px;
font-weight: bold;
vertical-align: top;
background-color: #87bc93;}

// <script>

// Copyright (C) 2005 Ilya S. Lyubinskiy. All rights reserved.
// Technical support: http://www.php-development.ru/
//
// YOU MAY NOT
// (1) Remove or modify this copyright notice.
// (2) Distribute this code, any part or any modified version of it.
//     Instead, you can link to the homepage of this code:
//     http://www.php-development.ru/javascripts/dropdown.php.
//
// YOU MAY
// (1) Use this code on your website.
// (2) Use this code as a part of another product provided that
//     its main use is not creating javascript menus.
//
// NO WARRANTY
// This code is provided "as is" without warranty of any kind, either
// expressed or implied, including, but not limited to, the implied warranties
// of merchantability and fitness for a particular purpose. You expressly
// acknowledge and agree that use of this code is at your own risk.

function expand(s)
{
  var td = s;
  var d = td.getElementsByTagName("div").item(0);

  td.className = "menuHover";
}

function collapse(s)
{
  var td = s;
  var d = td.getElementsByTagName("div").item(0);

  td.className = "menuNormal";
}

// ----- Popup Control ---------------------------------------------------------

function at_display(x)
{
  var win = window.open();
  for (var i in x) win.document.write(i+' = '+x[i]+'<br>');
}

// ----- Show Aux -----

function at_show_aux(parent, child)
{
  var p = document.getElementById(parent);
  var c = document.getElementById(child );

  var top  = (c["at_position"] == "y") ? p.offsetHeight+2 : 0;
  var left = (c["at_position"] == "x") ? p.offsetWidth +2 : 0;

  for (; p; p = p.offsetParent)
  {
    top  += p.offsetTop;
    left += p.offsetLeft;
  }

  c.style.position   = "absolute";
  c.style.top        = top +'px';
  c.style.left       = left+'px';
  c.style.visibility = "visible";
}

// ----- Show -----

function at_show()
{
  var p = document.getElementById(this["at_parent"]);
  var c = document.getElementById(this["at_child" ]);

  at_show_aux(p.id, c.id);

  clearTimeout(c["at_timeout"]);
}

// ----- Hide -----

function at_hide()
{
  var c = document.getElementById(this["at_child"]);

  c["at_timeout"] = setTimeout("document.getElementById('"+c.id+"').style.visibility = 'hidden'", 333);
}

// ----- Click -----

function at_click()
{
  var p = document.getElementById(this["at_parent"]);
  var c = document.getElementById(this["at_child" ]);

  if (c.style.visibility != "visible")
       at_show_aux(p.id, c.id);
  else c.style.visibility = "hidden";

  return false;
}

// ----- Attach -----

// PARAMETERS:
// parent   - id of visible html element
// child    - id of invisible html element that will be dropdowned
// showtype - "click" = you should click the parent to show/hide the child
//            "hover" = you should place the mouse over the parent to show
//                      the child
// position - "x" = the child is displayed to the right of the parent
//            "y" = the child is displayed below the parent
// cursor   - Omit to use default cursor or check any CSS manual for possible
//            values of this field

function at_attach(parent, child, showtype, position, cursor)
{
  var p = document.getElementById(parent);
  var c = document.getElementById(child);

  p["at_parent"]     = p.id;
  c["at_parent"]     = p.id;
  p["at_child"]      = c.id;
  c["at_child"]      = c.id;
  p["at_position"]   = position;
  c["at_position"]   = position;

  c.style.position   = "absolute";
  c.style.visibility = "hidden";

  if (cursor != undefined) p.style.cursor = cursor;

  switch (showtype)
  {
    case "click":
      p.onclick     = at_click;
      p.onmouseout  = at_hide;
      c.onmouseover = at_show;
      c.onmouseout  = at_hide;
      break;
    case "hover":
      p.onmouseover = at_show;
      p.onmouseout  = at_hide;
      c.onmouseover = at_show;
      c.onmouseout  = at_hide;
      break;
  }
}