function obsluga_menu(){
 inp=document.getElementsByTagName('div');
 for(i=0;i<inp.length;i++)
  with(inp[i])
   if(className=='section'){
    inp[i].onmouseover=new Function("if(this.className){this.className='section_on';}");
    inp[i].onmouseout=new Function("if(this.className){this.className='section';}");
   }
}

function switch_menu(obj){
 if(document.getElementById){
  var el = document.getElementById(obj);
  var ar = document.getElementById("leftbar").getElementsByTagName("div");
  if(el.style.display == "none"){
   for (var i=0; i<ar.length; i++)
    if(ar[i].className == "subsection") ar[i].style.display = "none";
   el.style.display = "block";
  }else{
   el.style.display = "none";
  }
 }
}