eh dai ok divertiamoci

codice:
<body>

<div id="ciao">ciao ciao</div>

<div id="hallo">hallo hallo</div>
test

<input type="checkbox" onclick="VediCheck('ciao', 'hallo', this)" />
<script>

function VediCheck(id,id2,ck){
String.prototype.x=function(){return !(this=='none')}
Boolean.prototype.x=function(){return (this.valueOf())?'none':'block';};
if(ck.nodeName=='INPUT'){
document.getElementById(id2).style.display=(document.getElementById(id).style.display=(ck.checked).x()).x().x();
}
else{
document.getElementById(id2).style.display=(document.getElementById(id).style.display=document.getElementById(id).style.display.x().x()).x().x();
};
}

</script>

</body>