if (document.layers) {
   var Lstart = "document.layers.";
   var Lstyle = "";  
   var visible = ".visibility = 'show'";
   var hide = ".visibility = 'hide'";}
else if (document.all) {
   Lstart = "document.all.";
   Lstyle = ".style"; 
   visible = ".visibility = 'visible'";
   hide = ".visibility = 'hidden'";}

function visi(name){
eval(Lstart+name+Lstyle+visible);}

function invisi(name){
eval(Lstart+name+Lstyle+hide);}