// JavaScript Document
function checkform() {
	var error_message="";
	if (document.gb_form.gb_firstname && document.gb_form.gb_firstname.value=="") {
		error_message +="First name\r\n";
	}
	if (document.gb_form.gb_lastname && document.gb_form.gb_lastname.value=="") {
		error_message +="Last name\r\n";
	}
	if (document.gb_form.gb_email.value.indexOf("@") == -1 || document.gb_form.gb_email.value.indexOf(".") == -1 || document.gb_form.gb_email.value.indexOf(" ") != -1) {
		error_message += "A valid email address\r\n";
	}
	if(error_message !=''){
		error_message='You need to fill in:\r\n' + error_message + '\r\n';
		alert(error_message);
		return false;
	}
}