var zoomfactor = 0.05;
  var maxsize;

  function zoomhelper(){
    if ((parseInt(whatcache.style.width) > 10 && parseInt(whatcache.style.height) > 10) &&
        (parseInt(whatcache.style.width) < maxsize && parseInt(whatcache.style.height) < maxsize)){
      whatcache.style.width  = parseInt(whatcache.style.width)  + parseInt(whatcache.style.width)  * zoomfactor * prefix + 'px';
      whatcache.style.height = parseInt(whatcache.style.height) + parseInt(whatcache.style.height) * zoomfactor * prefix + 'px';
      if (parseInt(whatcache.style.width) > maxsize){
        whatcache.style.height = (parseInt(whatcache.style.height) * maxsize) / parseInt(whatcache.style.width) + 'px';
        whatcache.style.width  = maxsize + 'px';
      }
      if (parseInt(whatcache.style.height) > maxsize){
        whatcache.style.width  = (parseInt(whatcache.style.width) * maxsize) / parseInt(whatcache.style.height) + 'px';
        whatcache.style.height = maxsize + 'px';
      }
    }
    else if (window.beginzoom)
      clearInterval(beginzoom);
  }

  function zoom(originalW, originalH, what, state, max_size){
    if (!document.all && !document.getElementById)
      return;
    whatcache = document.getElementById(what);
    prefix = 1; //(state == "in") ? 1 : -1;
    if (max_size)
      maxsize = max_size;
    else
      maxsize = 300; //default
    if (whatcache.style.width == "" || state == "restore"){
      whatcache.style.width  = originalW + 'px';
      whatcache.style.height = originalH + 'px';
      if (state == "restore")
        return;
    }
    else{
      zoomhelper();
    }
    beginzoom = setInterval("zoomhelper()", 100);
  }

  function clearzoom(){
    if (window.beginzoom)
      clearInterval(beginzoom);
  }