function aggiusta(altezza){
	
	num = parseInt(altezza)
	
	var IE = navigator.appName.indexOf("Microsoft") != -1;
	var filmato = IE ? document.getElementById("main") : document.main;
	if (self.innerHeight) // all except Explorer
	{
		h = self.innerHeight;
	}
	else if (document.documentElement && document.documentElement.clientHeight)
		// Explorer 6 Strict Mode
	{
		h = document.documentElement.clientHeight;
	}
	else if (document.body) // other Explorers
	{
		h = document.body.clientHeight;
	}
	if (h < num){
		hString = num + "px";
	} else {
		hString = "";
	}
	document.getElementById("main").style.height = hString;
	
	
}