php URL编码解码函数

<?php  
$url = "http://www.php.net";  
echo urlencode($url);                           //输出编码后的字符串  
?>

    <?php  
    $url = "http://www.php.net";  
    $newurl = urlencode($url);                          //首先对$url进行编码  
    echo urldecode($newurl);                            //输出解码后的字符串  
    ?>