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


function validate_email(email) {

	var reg = /^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
	return reg.test(email);
}


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 "";
}


function validateContactForm(form) {

	var errors = "";
	if(form.name.value == "")
		errors += "- Please enter your name<br />";

	if(form.email.value == "")
		errors += "- Please enter your e-mail address<br />";

	else if(!validate_email(form.email.value))
		errors += "- Please enter a valid e-mail address<br />";


	if(form.zipcode.value != "") {

		var reg = /^[0-9]{9}$/;
		if (!reg.test(form.zipcode.value)) {
			if(!validate_zipcode(form.zipcode.value))
				errors += "- Please enter a valid zip code<br />";
		}
	}

	if(form.phone_1.value != "" || form.phone_2.value != "" || form.phone_3.value != "") {
		var reg = /^[0-9]{10}$/;
		if(! reg.test("" + form.phone_1.value + "" + form.phone_2.value + "" + form.phone_3.value))
			errors += "- Please enter a valid phone number<br />";
	}

	if(form.comments.value == "")
		errors += "- Please enter your message<br />";

	if(errors != "") {
		document.getElementById('error_msg').innerHTML = errors;
		return false;
	}

	return true;
}