php URL编码解码函数代码

<?php
$url = "//www.jb51.net";
echo urlencode($url); //输出编码后的字符串
?>

<?php
$url = "//www.jb51.net";
$newurl = urlencode($url); //首先对$url进行编码
echo urldecode($newurl); //输出解码后的字符串
?>