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;    
}