function validate_numeric(number_string) {
	var reg = /^[0-9]+$/;
        return reg.test(number_string);
}


function validate_email(email) {
	
	var at_pos = email.indexOf("@");
	var email_length = email.length;
	var dot_pos = email.lastIndexOf(".");
	
	if(at_pos < 1 || dot_pos - at_pos < 2)
		return false;
  	else
  		return true;
}


function validate_zipcode(zipcode) {
	var reg1 = /^[0-9]{5}$/;
	var reg2 = /^[0-9]{5}\-[0-9]{4}$/;
	if(reg1.test(zipcode))
		return true;
	else if(reg2.test(zipcode))
		return true;
	else
		return false;
}


function validate_phonenumber(phonenumber) {
	var reg = /^[0-9]{3}\-[0-9]{3}\-[0-9]{4}$/;	
	return reg.test(phonenumber);
}


function validate_words(word_string) {
	var reg = /^[a-zA-Z\.\s\-'`]+$/;
	return reg.test(word_string);
}


function validate_domain(domain_string) {
	var reg = /^www\.[\w\-]+\.(com|net|org|edu|gov|int|mil)$/;
	return reg.test(domain_string);
}


function get_radio_value(button_group) {
	for(var i = 0; i < button_group.length; i++)
		if(button_group[i].checked)
			return button_group[i].value;
	
	return "";
}