document.write("<style> .hideshow {display:none; } </style>")
function show(cid){
  var thatstyle = document.getElementById(cid).style
  thatstyle.display=(thatstyle.display!="block")? "block" : "none"
}
/* example:  
	onclick="show('html')"
	<div id="html" class="hideshow" 
*/