var NS4 = (document.layers)?true:false;
var MSIE = (document.all)?true:false;
var NS6 = (navigator.userAgent.indexOf("Gecko")>0)?1:0;
var validdata;

function checkValid(){
validdata=true;
   for (i=1;i<12;i++){
      if ( (document.forms[0].elements[i].name).substring(0,5)=="oblig" ){
         nomeimg=document.forms[0].elements[i].name
         document.images[nomeimg].src='images/puntinografico.gif'
      }
	   if ( (document.forms[0].elements[i].name).substring(0,5)=="oblig"&&document.forms[0].elements[i].value==""){
	      validdata=false;
		  stringa = document.forms[0].elements[i].name.length
		  window.alert('Ricorda che il campo ' + (document.forms[0].elements[i].name).substring(5,stringa) + ' è obbligatorio');
		  document.images[nomeimg].src='images/puntinograficoan.gif'
		  document.forms[0].elements[i].focus();
		  return false;    	  
	   }
   }
   if (validdata){
   	  document.forms[0].submit();
   }
return false   
}