activateMenu = function(main_menu) {

    /* currentStyle restricts the Javascript to IE only */
	if (document.all && document.getElementById(main_menu).currentStyle) {  
        var main_menuroot = document.getElementById(main_menu);
        
        /* Get all the list items within the menu */
        var lis=main_menuroot.getElementsByTagName("LI");  
        for (i=0; i<lis.length; i++) {
        
           /* If the LI has another menu level */
            if(lis[i].lastChild.tagName=="UL"){
            
                /* assign the function to the LI */
             	lis[i].onmouseover=function() {	
                
                   /* display the inner menu */
                   this.lastChild.style.display="block";
                }
                lis[i].onmouseout=function() {                       
                   this.lastChild.style.display="none";
                }
            }
        }
    }
}