Mine

if(! isset($submit))
{
	form();
}
else
{
	$check_url = validate($url);
	if(empty($url) || empty($name))
	{
		form();
		die("");
	}
	else
	{
		if($check_url == "no") {
			echo "url must start with 'http://'";
			form();
			die();
		}

		//show new url
		if($_POST['url'] == !""){
			$query = "SELECT url FROM links WHERE url = '".rawurlencode($_POST['url'])."'";
			$result = mysql_query($query);
			if (mysql_num_rows($result) > 0) {
				echo 'url already exsits';
				form();
				} else {
					$genkey = create_key(12);
					$query  = 'INSERT INTO links (id,url,username,ip,genid) VALUES("'.$id.'","'.rawurlencode($_POST['url']).'","'.$_POST['name'].'","'.$ip.'","'.$genkey.'")';
					$result = mysql_query($query) or die($query);
					form();
					echo "<table border=1 width=500 align=center >
					<tr><td>Your new Url is::  ".$hosst."?go=" . $genkey ."<td></tr>" ;
					die();
				}
			}
		}
	}