function checkZip(form) {
	if(isNaN(document.getElementById("zip").value) || (document.getElementById("zip").value).length < 5) {
		alert("Please enter your zip code.");
		document.getElementById("zip").value = "";
		document.getElementById("zip").focus();
		return false;
	}
	
	form.action= form.action + "/" + form.zip.value;

	return true;
}