// position variation 1
function getOffset(e) {
    var x = 0;
    var y = 0;
    while (e && !isNaN(e.offsetLeft) && !isNaN(e.offsetTop)) {
        x += e.offsetLeft - e.scrollLeft;
        y += e.offsetTop - e.scrollTop;
        e = e.parentNode;
    }
    return { top: y, left: x };
}

// position variation 2
function findPosX(obj) {
   var curleft = 0;
   if (obj.offsetParent) {
      while(1) {
         curleft += obj.offsetLeft;
         if (!obj.offsetParent)
            break;
         obj = obj.offsetParent;
       }
   }
   else if(obj.x) {
      curleft += obj.x;
   }
   return curleft;
}

// shows the drop-down menu
function showMenu(b, nav, menu) {
	var oNav2 = document.getElementById(nav);
	var oMenu = document.getElementById(menu);

	// current nav2 x position
	var xNav2 = findPosX(oNav2); // getOffset(oNav2);

	// reinforce positioning
	if (oMenu.style.left != xNav2) {
		oMenu.style.left = xNav2;
	}

	// show/hide
	oMenu.style.visibility = b ? "visible" : "hidden";
	oMenu.style.display = b ? "inline" : "none";
}

// on click, exit menu then proceed to selected page
function hrefMenu(url, nav, menu) {
	showMenu(false, nav, menu);
	document.location.href = url;
}