window.onload = 
function MenuHead(){
  if (document.all && document.getElementById) {
  	menuHead = document.getElementById("menu");
    for (i=0; i < menuHead.childNodes.length; i++) {
      menuItems = menuHead.childNodes[i];
      if (menuItems.nodeName == "LI") {
        menuItems.onmouseover = 
	        function overItems(){
	          this.className += " over";
	          ShowHideSelect('hidden')
		      }
        menuItems.onmouseout = 
        	function outItems(){
	          this.className = this.className.replace(" over", "");
	          ShowHideSelect('visible')
        	}
      }
    }
  }
}	


//skryje a zobrazi SELECT
function ShowHideSelect(vis){
	sel = document.getElementsByTagName('select');
	for(i = 0; i < sel.length; i++){
    sel[i].style.visibility = vis;
  }
}