HM_DOM = (document.getElementById) ? true : false;
HM_NS4 = (document.layers) ? true : false;
HM_IE = (document.all) ? true : false;
HM_IE4 = HM_IE && !HM_DOM;
HM_Mac = (navigator.appVersion.indexOf("Mac") != -1);
HM_IE4M = HM_IE4 && HM_Mac;
HM_Opera = (navigator.userAgent.indexOf("Opera")!=-1);
HM_Konqueror = (navigator.userAgent.indexOf("Konqueror")!=-1);
HM_Safari = (navigator.vendor == 'KDE' || ( document.childNodes && !document.all && !navigator.taintEnabled ));
HM_IsMenu = !HM_Opera && !HM_Konqueror && !HM_IE4M && (HM_DOM || HM_NS4 || HM_IE4);
HM_BrowserString = HM_NS4 ? "NS4" : HM_DOM ? "DOM" : "IE4";
HM_IE_version = (HM_IE) ? parseFloat(navigator.appVersion.split("MSIE")[1]) : null;


//allows DIV tags to show over SELECT boxes
//  various browsers have trouble with this
function hideSelectBoxes(el, on)
{

	this.getValue=function(s){
		return (new String(s).indexOf('px')!=-1)?s:s+'px';
	};

  if (( (HM_IE || HM_DOM) && !HM_Mac && !HM_Opera) || HM_Safari)
  {
    //get menu dimensions
    var p = getAbsolutePosition(el);

    
    if (HM_IE_version >= 5.5)
    {
      //in this case, we create an IFRAME that sits just under the div tag
      //this is done because IE 5.5+ exibits the strange behaviour that
      //an iframe can be displayed over a select box AND under a div tag
      //but a div tag, by itself, can never go over a select box
      //so, by layering them like this, the menu is properly displayed
      
      var iframeID = el.id+"_hide_iframe";

      var myIframe;
      myIframe = document.getElementById(iframeID)
      if(!myIframe){
      	myIframe = document.createElement("IFRAME");
        myIframe.setAttribute("id", iframeID);
        document.body.appendChild(myIframe);
      }
      myIframe.style.display = (on) ? "" : "none";
      myIframe.style.visible="hidden";
      
      myIframe.style.border=0;
      myIframe.style.position='absolute';
      myIframe.style.left=0;
      myIframe.style.top=0;
      
      myIframe.style.width=this.getValue(el.offsetWidth);
      myIframe.style.height=this.getValue(el.offsetHeight);
      
      myIframe.style.zIndex=-100;
      myIframe.style.filter="Alpha(opacity=0)";
        
    }
    else //IE version is below 5.5
    {
      //in this case, the browser will not allow a div to be displayed
      //over a select box no matter what, so we simply grab all the
      //select boxes and hide them if there is overlap with the new menu
      //or show them if the menu is closing
      
      //get menu dimensions
      
      var HM_EX1 = p.x;
      var HM_EX2 = el.offsetWidth + HM_EX1;
      var HM_EY1 = p.y;
      var HM_EY2 = el.offsetHeight + HM_EY1;
      
      //now get all "trouble" elements
      var tags = new Array("applet", "select","object","embed");
      
      for (var k=0; k<tags.length; k++ )
      {
        var elems = document.getElementsByTagName(tags[k]);
        var elem = null;
        
        for (var i=0; i<elems.length; i++)
        {
          elem = elems[i];
          
          //get elem dimensions
          p = getAbsolutePosition(elem);
          var HM_CX1 = p.x;
          var HM_CX2 = elem.offsetWidth + HM_CX1;
          var HM_CY1 = p.y;
          var HM_CY2 = elem.offsetHeight + HM_CY1;

          if ( !((HM_CX1 > HM_EX2) || (HM_CX2 < HM_EX1) || (HM_CY1 > HM_EY2) || (HM_CY2 < HM_EY1)) && !isDescendant(el, elem) )
          {
            //elements overlap, hide or show elem
            if (on)
            {
              //save old value
              elem[el.id] = elem.style.visibility;
              
              //hide element
              elem.style.visibility = "hidden";
            }
            else
            {
              //restore old value
              elem.style.visibility = elem[el.id];
            }
          }
        }
      }
    }
  }
}

function isDescendant(child,ancestor){
	if( typeof(ancestor) == "undefined" || ancestor == null )
		return false;
	else if( child == ancestor )
		return true; 
	else if( ancestor.id == child.id ) 
		return true; 
	else if( ancestor.parentNode == child.parentNode)
		return false;
	else
		return isDescendant( child, ancestor.parentNode);
}

// finds position on page, even for inline elements
function getAbsolutePosition(elem)
{
  var r = { x: elem.offsetLeft, y: elem.offsetTop };
  if (elem.offsetParent)
  {
    var tmp = getAbsolutePosition(elem.offsetParent);
    r.x += tmp.x;
    r.y += tmp.y;
  }
  return r;
}

function moveIFrame(el) {
	var iframeID = el.id+"_hide_iframe";
	var myIframe;
	if (myIframe = document.getElementById(iframeID)) {
		myIframe.style.top = el.style.top;
		myIframe.style.left = el.style.left;
	}
}