// preload images ...
  var aSubMenu = new Array(14);
  for (i=0; i<14; i++) {aSubMenu[i] = new Image();}

  aSubMenu[0].src = 'http://www.qualityuvlamps.com/images/aquanetic_on.gif';
  aSubMenu[1].src = 'http://www.qualityuvlamps.com/images/aquanetic_off.gif';
  aSubMenu[2].src = 'http://www.qualityuvlamps.com/images/aquaultraviolet_on.gif';
  aSubMenu[3].src = 'http://www.qualityuvlamps.com/images/aquaultraviolet_off.gif';
  aSubMenu[4].src = 'http://www.qualityuvlamps.com/images/dannersupreme_on.gif';
  aSubMenu[5].src = 'http://www.qualityuvlamps.com/images/dannersupreme_off.gif';
  aSubMenu[6].src = 'http://www.qualityuvlamps.com/images/hozelockcyp_on.gif';
  aSubMenu[7].src = 'http://www.qualityuvlamps.com/images/hozelockcyp_off.gif';
  aSubMenu[8].src = 'http://www.qualityuvlamps.com/images/pentairlife_on.gif';
  aSubMenu[9].src = 'http://www.qualityuvlamps.com/images/pentairlife_off.gif';
  aSubMenu[10].src = 'http://www.qualityuvlamps.com/images/tetra_on.gif';
  aSubMenu[11].src = 'http://www.qualityuvlamps.com/images/tetra_off.gif';
  aSubMenu[12].src = 'http://www.qualityuvlamps.com/images/emperor_on.gif';
  aSubMenu[13].src = 'http://www.qualityuvlamps.com/images/emperor_off.gif';
  // swap submenu images ...
  function swapSubMenu(sSubMenuName, nSubMenuIndex) {
    document[sSubMenuName].src = aSubMenu[nSubMenuIndex].src;
		return true;
  }


  var inSubMenu = false;

  // show layer ...
  function showSubMenu(sSubMenuName) {

    // cross-browser function to get an object's style object given its id
    if(document.getElementById && document.getElementById(sSubMenuName)) {
	    // W3C
	    document.getElementById(sSubMenuName).style.visibility = 'visible';
    } else if (document.all && document.all(sSubMenuName)) {
	    // IE 4
	    document.all(sSubMenuName).style.visibility = 'visible';
    } else if (document.layers && document.layers[sSubMenuName]) {
	    // NS 4
	    document.layers[sSubMenuName].visibility = 'show';
    } 

  }

  // hide layer ...
  function hideSubMenu(sSubMenuName) {

    if (!inSubMenu) {
    
      // cross-browser function to get an object's style object given its id
      if(document.getElementById && document.getElementById(sSubMenuName)) {
	      // W3C
	      document.getElementById(sSubMenuName).style.visibility = 'hidden';
      } else if (document.all && document.all(sSubMenuName)) {
	      // IE 4
	      document.all(sSubMenuName).style.visibility = 'hidden';
      } else if (document.layers && document.layers[sSubMenuName]) {
	      // NS 4
      document.layers[sSubMenuName].visibility = 'hide';
      }

    }

  }

  function delayHideSubMenu(sSubMenuName) {
    window.setTimeout("hideSubMenu('" + sSubMenuName + "')", 5000);
  }