var browser=navigator.userAgent;
 function sichten(id,wat)
{
 var welch=document.getElementById(id);
 var wech= document.getElementById('rahm');
        	if (welch.style.visibility == "hidden")
	   {
	    wech.src='bilder/'+wat+'gr.jpg';
             welch.style.display='inline';
	    welch.style.visibility ="visible";

 }
	else
	 {
	  welch.style.visibility ="hidden";
           welch.style.display='none';
	  wech.src='bilder/leer.gif';
          }
	 //alert(wech.src);
 }

function pop(id,o,wat,wa)
{

       if(document.layers)
	{
		urspW=window.innerWidth;
		urspH=window.innerHeight;
	}
	else if(((!document.all)&&(document.getElementById)) || navigator.userAgent.indexOf("Opera") != -1)
	{
	urspW=window.innerWidth;
	urspH=window.innerHeight;
	}
	else if(document.all)
	{
	urspW=document.body.clientWidth;
	urspH=document.body.clientHeight;
	}
	else
	{
	urspH=500;
	}
        mitte= urspH/2;
        zenter= urspW/2;

        ziel=document.getElementById(id);
        ziel.style.left=(zenter+o);
        ziel.style.top=mitte-wa;

        sichten(id,wat);

        }