code: function writeNetscapeExt() {
      out.writeByte(0x21); // extension introducer
      out.writeByte(0xff); // app extension label
      out.writeByte(11); // block size
      out.writeUTFBytes("NETSCAPE" + "2.0"); // app id + auth code
      out.writeByte(3); // sub-block size
      out.writeByte(1); // loop sub-block id
      WriteShort(repeat); // loop count (extra iterations, 0=repeat forever)
      out.writeByte(0); // block terminator
    }
docs: Writes Netscape application extension to define repeat count.