var req = new XMLHttpRequest();
url = "http://slug.realraum.at/cgi-bin/switch.cgi?power=send&id="+btn;
req.open("GET", url ,false);
+ //google chrome workaround
+ req.setRequestHeader("googlechromefix","");
req.send(null);
//response = req.responseText;
//document.getElementById('output').innerHTML = response;