// JavaScript Document
function anzeigen(element)
{
  if(document.getElementById(element).style.display=='none') 
   document.getElementById(element).style.display='block'; 
  else document.getElementById(element).style.display='none';
  }
 
#variablen_theorie {
	position:relative;
	display:none;
	z-index:1;
}
#if_theorie {
	position:relative;
	display:none;
	z-index:1;
}