function MM_showHideLayers() { //v2.0
  var i, visStr, args, theObj;
  args = MM_showHideLayers.arguments;
  for (i=0; i<(args.length-2); i+=3) { //with arg triples (objNS,objIE,visStr)
    visStr   = args[i+2];
    if (navigator.appName == 'Netscape' && document.layers != null) {
      theObj = eval(args[i]);
      if (theObj) theObj.visibility = visStr;
    } else if (document.all != null) { //IE
      if (visStr == 'show') visStr = 'visible'; //convert vals
      if (visStr == 'hide') visStr = 'hidden';
      theObj = eval(args[i+1]);
      if (theObj) theObj.style.visibility = visStr;
  } }
}

function menu1on() {MM_showHideLayers('document.layers[\'Layer1\']','document.all[\'Layer1\']','show')}
function menu2on() {MM_showHideLayers('document.layers[\'Layer2\']','document.all[\'Layer2\']','show')}
function menu3on() {MM_showHideLayers('document.layers[\'Layer3\']','document.all[\'Layer3\']','show')}
function menu4on() {MM_showHideLayers('document.layers[\'Layer4\']','document.all[\'Layer4\']','show')}
function menu5on() {MM_showHideLayers('document.layers[\'Layer5\']','document.all[\'Layer5\']','show')}

function menu1off() {MM_showHideLayers('document.layers[\'Layer1\']','document.all[\'Layer1\']','hide')}
function menu2off() {MM_showHideLayers('document.layers[\'Layer2\']','document.all[\'Layer2\']','hide')}
function menu3off() {MM_showHideLayers('document.layers[\'Layer3\']','document.all[\'Layer3\']','hide')}
function menu4off() {MM_showHideLayers('document.layers[\'Layer4\']','document.all[\'Layer4\']','hide')}
function menu5off() {MM_showHideLayers('document.layers[\'Layer5\']','document.all[\'Layer5\']','hide')}