function showimage (divobj) {
        var browser=navigator.appName;
          divobj.style.visibility = 'visible';
      }
      function hideimage (divobj) {
        var browser=navigator.appName;
          divobj.style.visibility = 'hidden';
      }

      var timeout	= 500;
      var closetimer	= 0;
      var ddmenuitem	= 0;

      // open hidden layer
      function mopen(id) {	
	// cancel close timer
	mcancelclosetime();

	// close old layer
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

	// get new layer and show it
	ddmenuitem = document.getElementById(id);
	ddmenuitem.style.visibility = 'visible';

      }
      // close showed layer
      function mclose() {
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
      }

      // go close timer
      function mclosetime() {
	closetimer = window.setTimeout(mclose, timeout);
      }

      // cancel close timer
      function mcancelclosetime() {
	if(closetimer) 	{
	  window.clearTimeout(closetimer);
	  closetimer = null;
	}
      }

      // close layer when click-out
      document.onclick = mclose;