foreach (explode("\n", $diff_str) as $line) {
        if (ord($line) == 0x2d) {
            $diff_from_default4disp .= "<span style='color:red;'>" . $line . "</span>\n";
        } elseif (ord($line) == 0x2b) {
            $diff_from_default4disp .= "<span style='color:blue;'>" . $line . "</span>\n";