function check_input(){ 
   var message_alert = ""; 
   for(var i = 0; i < window.document.forms[0].length ; i++) { 
      var rechRapide = window.document.forms[0].elements[i].value; 
      var nom_champ = window.document.forms[0].elements[i].name; 
      window.document.forms[0].elements[i].style.backgroundColor = "#FFFFFF"; 
      if(rechRapide == "") { 
         window.document.forms[0].elements[i].focus(); 
         window.document.forms[0].elements[i].style.backgroundColor = "#CCCCCC"; 
         message_alert +=" Veuillez remplir le champ " + nom_champ +"\n"; 
      } 
   } 
   if (message_alert == "") { 
         return true; 
      } else { 
         message_alert = "Informations omises dans le formulaire : \n" + message_alert; 
         alert(message_alert); 
         return false; 
         } 
} // JavaScript Document