function Browser() {

  var ua, s, i;

  this.isIE    = false;  // Internet Explorer
  this.version = null;

  ua = navigator.userAgent;

  s = "MSIE";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isIE = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }
}

var browser = new Browser();


function openSubMenu(menuname) {

	if (browser.isIE)
    	document.getElementById(menuname).style.visibility = "visible";
}
function closeSubMenu(menuname) {
	if (browser.isIE)
 	   document.getElementById(menuname).style.visibility = "hidden";
}