var stato = new Array();

if (document.getElementById){
   document.write('<style type="text/css">')
   document.write('.switch{display:none;}')
   document.write('</style>')
}


function trigger(elem){
   if (stato[elem]=="block") stato[elem]="none";
   else stato[elem]="block";

   document.getElementById(elem).style.display=stato[elem];
}