function checkCatalogue(){
	var email_reg_exp 	= /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/;
	if (document.login.username.value == ""){
		alert('INSERIRE USERNAME');
		document.login.username.focus();
	}
	else if (document.login.username.value != "" && !email_reg_exp.test(document.login.username.value)){
		alert('EMAIL NON CORRETTA');
		document.login.username.value = '';
		document.login.username.focus();
	}
	else if (document.login.password.value == ""){
		alert('INSERIRE PASSWORD');
		document.login.password.focus();
	}
	else{
		document.login.action = '../brake/modules/AreaRiservata/check.php';
		document.login.submit();
	}
}