function showAnbieter(letter) { 
		var req;
		req = window.XMLHttpRequest?new XMLHttpRequest(): 
		new ActiveXObject("Microsoft.XMLHTTP");
		
		req.onreadystatechange = function() {
			if ((req.readyState == 4) && (req.status == 200)) { 
				document.getElementById('output').innerHTML = req.responseText;	
				document.getElementById('letter_'+ letter).innerHTML = ("<strong>"+letter+"</strong>");

			}	
		};
			
		req.open('GET', 'handler.php?show='+letter, true);
		req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        req.setRequestHeader("charset", "charset=iso-8859-1");
		req.send(null);
}