var dom = document.getElementById ? true : false; 
var menu_el='menu';

function X(eElement)
{
    var nLeftPos = eElement.offsetLeft;
    var eParElement = eElement.offsetParent; 
    while (eParElement != null)
    {
        nLeftPos += eParElement.offsetLeft;
        eParElement = eParElement.offsetParent;
    }
    return nLeftPos;
}

function Y(eElement)
{
    var nTopPos = eElement.offsetTop;
    var eParElement = eElement.offsetParent;
    while (eParElement != null)
    {                                           
        nTopPos += eParElement.offsetTop;        
        eParElement = eParElement.offsetParent;  
    }
    return nTopPos;                              
}


function show() {
  lis = this.childNodes;
  this.parentNode.style.background_image = "url('images/bus_menu_pozadi.png')";
  first = ( this.parentNode.id == menu_el )? true : false; 
  pos_x =  ( first )? X( this ) : 0;
  pos_y =  ( first )? Y( this ) + this.offsetHeight : 0;
  for ( i=0; i < lis.length; i++ ) {
    if ( lis[i].tagName == 'UL' ) {
	  lis[i].style.left = pos_x + 'px';
      lis[i].style.top =  pos_y + 'px';	
	  lis[i].style.position = 'absolute';
	  lis[i].style.display = 'block';
	  lis[i].onmouseout = hide_self; 
	  break;
	}    
  }
}


function hide_self() {
  this.style.display = 'none';
}


function hide() {
  lis = this.childNodes;
  for ( i=0; i < lis.length; i++ ) {
    if ( lis[i].tagName == 'UL' ) {
	  lis[i].style.display = 'none';
	}    
  }
}


function start( oLink ) {
  lis = oLink.getElementsByTagName('UL');
  for ( i=0; i < lis.length; i++ ) {
    if (lis[i].tagName == 'UL') {
	  lis[i].parentNode.onmouseover = show;
	  lis[i].parentNode.onmouseout = hide;
	  lis[i].style.display = 'none';
	}
  }
}