var menuids=["menu_principal_javascript"] 

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++){
		if (ultags[t].parentNode.parentNode.id==menuids[i]){		
			ultags[t].style.top=ultags[t].parentNode.offsetHeight+"px"
		}
		else{
		  ultags[t].style.left=ultags[t-1].getElementsByTagName("a")[0].offsetWidth+"px"
		}
        ultags[t].parentNode.onmouseover=function(){
            this.getElementsByTagName("ul")[0].style.visibility="visible"
						
        }
        ultags[t].parentNode.onmouseout=function(){
            this.getElementsByTagName("ul")[0].style.visibility="hidden"
        }
    }
}
}

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