php 正确解码javascript中通过escape编码后的字符

这是很久以前收集的一个,不知道谁写的了,但经过测试没有问题~
javascript代码

function phpunescape($escstr)
{
preg_match_all("/%u[0-9a-za-z]{4}|%.{2}|[0-9a-za-z.+-_]+/", $escstr, $matches);
$ar = &$matches[0];
$c = "";
foreach($ar as $val)
{
if (substr($val, 0, 1) != "%")
{
$c .= $val;
} elseif (substr($val, 1, 1) != "u")
{
$x = hexdec(substr($val, 1, 2));
$c .= chr($x);
}
else
{
$val = intval(substr($val, 2), 16);
if ($val < 0x7f) // 0000-007f
{
$c .= chr($val);
} elseif ($val < 0x800) // 0080-0800
{
$c .= chr(0xc0 | ($val / 64));
$c .= chr(0x80 | ($val % 64));
}
else // 0800-ffff
{
$c .= chr(0xe0 | (($val / 64) / 64));
$c .= chr(0x80 | (($val / 64) % 64));
$c .= chr(0x80 | ($val % 64));
}
}
}
return $c;
}

escape编码后:

%u6d4b%u8bd5www.jb51.net%22%22%27%27%3c%3e%26%26

解码后:

测试www.jb51.net""''<>&&