// tld-check.php

<?php
$dname = $_REQUEST['domain'];
$tname = $_REQUEST['tld'];
$submit = $_REQUEST['submit'];

if (isset($submit) && isset($dname) && isset($tname)) {
	
	$site = file_get_contents('http://isfree.schlundtech.de/cgi-bin/isfree.cgi?domain=' .$dname. '.' .$tname. '&lang=EN');

	if (strpos($site, 'is still available') !== false) {	
		$results = "<b>$domain is Available</b>";
	} else {
		$results = "<b>$domain is Not Available</b>";
	}
}
?>	


// form 
<form action="tld-check.php" method="post" id="check">
<input type="text" name="domain" id="domain" size="18"> 
   <select name="tld" id="tld" size="1">
         <option id="com" value="com" selected>com</option>
         <option id="net" value="net">net</option>
         <option id="org" value="org">org</option>
         <option id="biz" value="biz">biz</option>
   </select>
</form>

// NOTE: the submit button is outside the form wrapper

<input type="image" src="images/search-but.gif" width="53" height="21" onclick="document.forms['check'].submit();" name="submit"/>