function toggle_menu (elem) {
 untoggle_all_menus();
 elem.className = 'menu_on';
 imgs = elem.getElementsByTagName('IMG');
 img = imgs[0];
 img.src = img.getAttribute('enabledsrc');
 divs = elem.getElementsByTagName('DIV');
 if(divs[0]) {
  menudiv = divs[0];
  menudiv.className='menu_show';
 }
}

function untoggle_all_menus() {
 menu_table = document.getElementById('menu');
 tds = menu_table.getElementsByTagName('TD');
 for(i = 0; i < tds.length; i++) {
  td = tds[i];
  if(td.className != 'menu_off') {
   td.className = 'menu_off';
   imgs = td.getElementsByTagName('IMG');
   img = imgs[0];
   img.src = img.getAttribute('disabledsrc');
   divs = td.getElementsByTagName('DIV');
   if(divs[0]) {
    menudiv = divs[0];
    menudiv.className='menu_hidden';
   }
  }
 }
}

function change_background(naam, naam2) {
 elem = document.getElementById('top_background');
 if(elem.className != 'bg_3_2_'+naam) {
  elem.className = 'bg_3_2_'+naam;
 }
 if(naam2) {
  elem2 = document.getElementById('bg_4_1');
  if(elem2.className != 'bg_4_1_'+naam2) {
   elem2.className = 'bg_4_1_'+naam2;
  }
 }
}

function get_url(url)
  {
  var xmlHttp;
  try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
    }
  catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      try
        {
        xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
        }
      catch (e)
        {
        alert("Your browser does not support AJAX!");
        return false;
        }
      }
    }
    xmlHttp.onreadystatechange=function()
      {
      if(xmlHttp.readyState==4)
        {
        inhoudvak = document.getElementById('inhoud');
        inhoudvak.innerHTML = xmlHttp.responseText;
        }
      }
    xmlHttp.open("GET",url,true);
    xmlHttp.send(null);
    untoggle_all_menus();
  }