Format: 123-45-678



 	
 	$("#sendBtn").click(function (event) {
			event.preventDefault();
	
 			if($("#cognome").val()===''  )
            {
				$("#cognome").attr("placeholder", "NON HAI INSERITO IL COGNOME");
				$("#cognome").css({"background-color":"#f6f6a4","border": "red 2px solid"}); 
				return false;
			 }	
            
 			 
		 
	});