function controllo_form(){
	var spia=true;
	var modello=/^\w+$/;
	var form=document.form;

	for (var i=0;i<form.length;i++){
		//if(modello.test(form.elements[i].value)==false) {
		  if(form.elements[i].value=="") {
			alert("campo "+ form.elements[i].name+" vuoto");
			spia=false;
		}
	}
	if(spia==true) {
		var modelloeta=/^\d+$/;
		var modelloposta=/\w+(\.\w+)?@\w+\.\w+/;
			if(modelloposta.test(form.email.value)==false) {
			alert("Indirizzo e-mail errato");
			spia=false;
		}

	}
	return spia;

}  
  
  <!--
 function Photogallery(g) {
   var w = 600;
   var h = 530;
   var l = Math.floor((screen.width-w)/2);
   var t = Math.floor((screen.height-h)/2);
      window.open(g,"","scrollbars=no,width=" + w + ",height=" + h + ",top=" + t + ",left=" + l);
 }
 //-->