在php反处理经过JavaScript中escape方法处理的数据

函数如下：

function js_unescape($str) 
{ 
        $ret = ''; 
        $len = strlen($str); 
 
        for ($i = 0; $i < $len; $i++) 
        { 
                if ($str[$i] == '%' && $str[$i+1] == 'u') 
                { 
                        $val = hexdec(substr($str, $i+2, 4)); 
 
                        if ($val < 0x7f) $ret .= chr($val); 
                        else if($val < 0x800) $ret .= chr(0xc0|($val>>6)).chr(0x80|($val&0x3f)); 
                        else $ret .= chr(0xe0|($val>>12)).chr(0x80|(($val>>6)&0x3f)).chr(0x80|($val&0x3f)); 
 
                        $i += 5; 
                } 
                else if ($str[$i] == '%') 
                { 
                        $ret .= urldecode(substr($str, $i, 3)); 
                        $i += 2; 
                } 
                else $ret .= $str[$i]; 
        } 
        return $ret; 
}