//USAGE: $results .=(Continuous for multiple fields) formcheck($postdata,"Field",length(number),"A or AN, ALL, EMAIL, WEBSITE, etc.","REQUIRE, NA");
//EXAMPLE: $results .= formcheck($postdata,"Name",30,"AN","REQUIRE"); Then check $results for errors. If == "" then process form.
function formcheck($data,$field,$length,$type,$require) {
	if ($data == "" && $require == "REQUIRE") {
		$error .= "<li class=\"errors\"><b>" . $field . "</b> Cannot be left blank</li>";
		return $error;
	} elseif ($data == "" && $require =="NA") {
		return;
	}
	
	if (strlen($data) > $length) $error .= "<li class=\"errors\"><b>" . $field . "</b> is too long. Please use <b>" . $length . "</b> characters or less.</li>";

	switch($type) {
		case "AN": if (!preg_match("/^[a-z0-9 ]+$/i", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> can only contain letters and numbers and spaces</li>"; break;
		case "A": if (!preg_match("/^[a-z]+$/i", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> can only contain letters and spaces</li>"; break;
		case "N": if (!preg_match("/^[0-9]+$/", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> can only contain numbers</li>"; break;
		case "ALL": if(!preg_match("/^[a-z0-9\:\-\_\?\&\;\#\.\"\/\,\'\\\ ]+$/i", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> contains invalid characters</li>"; break; //htmlspecialchars($data); better to do this for general data
		case "DATE": if(preg_match("/^[0-9]{2}-[0-9]{2}-[0-9]{4}$/", $data) === 0) $error .= "<li class=\"errors\"><b>" . $field . "</b> must be in the format MM-DD-YYYY</li>"; break;
		case "PASS": if(!preg_match("/^.*(?=.{6,})(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z]).*$/", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> must be at least 6 characters with at least one lower case letter, one upper case letter & one digit.</li>";
		case "WEBSITE": if (!preg_match("/^[a-z0-9\.\/\-:]+$/i", $data)) $error .= "<li class=\"errors\"><b>" . $field . "</b> entered is invalid.</li>"; break;
		case "EMAIL": if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $data)) $error .= "<li class=\"errors\">The <b>" . $field . "</b> address entered is invalid.</li>"; break;
	}
	
	return $error;
}