<html><head>
<title>Zip code checker</title>
</head>
<body bgcolor="#fad888" text="black">
<form>
<center>
<input type="text" name="in" value="<? echo "$in"; ?>">
<input type="submit" value="Is it a zip code?"><br />
<?
$in = $_REQUEST[in];
if ( !isset($in))
{ echo "Enter a zip code"; }
elseif ( isset($in) && ereg("^[0-9]{5}(\-[0-9]{4})?$", $in) )
{ echo "$in looks like a zip code"; }
else
{ echo "$in does not look like a zip code"; }
?>
</center>
</form>
</body>
</html>