function validateForm(){
	var emailReg = "^[\\w-_\.]*[\\w-_\.]\@[\\w]\.+[\\w]+[\\w]$";
	var regex = new RegExp(emailReg);
	var val = document.signup_form.email.value;
	if(val == ''){
		alert("you have not entered an email address");
	}else if(!regex.test(val)){
		alert("you have entered an invalid email address");
	}else{
		submit();
	}
}