var menuids=["menu1"]

function buildsubmenus_horizontal(){
for (var i=0; i<menuids.length; i++){
  var ultags=document.getElementById(menuids[i]).getElementsByTagName("ul")
    for (var t=0; t<ultags.length; t++){
		ultags[t].parentNode.onmouseover=function(){
			this.getElementsByTagName("ul")[0].style.display="block"
		}
		
		ultags[t].parentNode.onmouseout=function(){
			this.getElementsByTagName("ul")[0].style.display="none"
		}
		
    }
  }
}

if (window.addEventListener)
window.addEventListener("load", buildsubmenus_horizontal, false)
else if (window.attachEvent)
window.attachEvent("onload", buildsubmenus_horizontal)