Ecco:
codice:
<HTML>
<HEAD>
<script>
var y="";
var x="";
function cambia(questo,what){
	
	if(what=="fix" ){
					  if(y!="")giraImg(y);
					  y=questo.id;
					  }
	if(y!=questo.id)giraImg(questo.id);
}

function giraImg(x){

	var source="";
	var end=document.getElementById(x).src.length;

	for(i = 0; i<(end-5); i++){ 
		source= source + document.getElementById(x).src.charAt(i);
	}
	
	if(document.getElementById(x).src.charAt(end-5)==1) {source= source+'2.jpg'}
	else {source= source+'1.jpg'};
	
	document.getElementById(x).src=source;
  
}
</script>
</HEAD>
<BODY>
[img]logo1.jpg[/img]


[img]img1.jpg[/img]
</BODY>
</html>