function validate() {
	var signup_form = document.forms["sign_up"];
	if (field_is_empty(signup_form.cn, kSponsorName)) return false;
	if (field_is_empty(signup_form.fn, kFirstName)) return false;
	if (field_is_empty(signup_form.ln, kLastName)) return false;
	if (!validate_email(signup_form.ea.value)) {
		alert(kEmailAddress);
		signup_form.ea.focus();
		return false;
	}
	if (signup_form.co.value == "") {
		alert(kCountry);
		signup_form.co.focus();
		return false;
	}
	if (field_is_empty(signup_form.pw, kPassword)) return false;
	if(signup_form.pw.value != signup_form.cp.value) {
		alert(kPasswordMatch);
		signup_form.pw.focus();
		return false;
	}
	if (field_is_empty(signup_form.bt, kBannerText)) return false;
	signup_form.h.value = hex_sha1(signup_form.pw.value);
	signup_form.pw.value = "";
	signup_form.cp.value = "";
	signup_form.bk.value = massage_link(signup_form.bk.value);
	return true;
}

function populate_text() {
	var signup_form = document.forms["sign_up"];
	if (signup_form.bt.value == "") {
		signup_form.bt.value = signup_form.cn.value;
	}
}

function populate_link() {
	var signup_form = document.forms["sign_up"];
	if (signup_form.bk.value == "") {
		signup_form.bk.value = "mailto:" + signup_form.ea.value;
	}
}