function zipCheck(form) {
	if(form.zip.value == "") {
		alert("Please enter your zip code.");
		return false;
	} else if(isNaN(form.zip.value)) {
		alert("Please enter your zip code.");
		return false;
	} else if(form.zip.value.length < 5) {
		alert("Please enter your zip code.");
		return false;
	} else {
		return true;
	}
}