function dropDownNav()	{
	if (!document.getElementById)	{
		window.alert('Your browser does not support the scripting required for this site.');
		return false;
	}
	var mainNavList = document.getElementById('main_nav_bar');
	var children = mainNavList.childNodes.length;
	for(i=0;i<children;i++)	{
		var currNode = mainNavList.childNodes[i];
		if (currNode.nodeName == 'LI')	{
			currNode.onmouseover = function()	{
				this.className = 'over';
			}
			currNode.onmouseout = function()	{
				this.className = '';
			}
		}
	}
}