codice:
<html>
<head>
<title>Documento senza titolo</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script>
function controlla_quantita(ff, nom){
  var n = 0;
  var cc = ff.elements[nom];
	
  for (var i=0; i<cc.length; i++) {
	  if(cc[i] == ''){
		  alert("CAMPO "+cc[i]+" VUOTO");
		  cc[i].focus();
		  cc[i].select();
		  }else if(!(cc[i].match(/^(\+)?(\d)+$/))){
			  alert("INSERIRE UN NUMERO");
			  cc[i].focus();
			  cc[i].select();
			  }else{
				  n++
			  }
  }
    if(n>0) {
	  window.alert("posso modificare")
	  return false;
		
	}
}
</script>
</head>

<body>
<form name="form1" id="form1" method="post" action="">
<input name="quantita" type="text" class="carrello_input" id="quantita33" value="5">
<input name="quantita" type="text" class="carrello_input" id="quantita34" value="5">
[img]../images/pulsanti/aggiorna_it.jpg[/img]
</form>
</body>
</html>