bidder.xml

<Module>
  <ModulePrefs title="Wave Bidding" height="250">
    <Require feature="rpc"/>
  </ModulePrefs>

  <Content type="html">
  <![CDATA[
  <script type="text/javascript"
      src="http://wave-api.appspot.com/public/wave.js"></script>
  <script type="text/javascript">
    function buttonClicked() {
      var viewerId = wave.getViewer().getId();
      var state = wave.getState();
      var bid = parseInt(document.getElementById('yourBid').value);
      var currentBid = parseInt(state.get(viewerId, '0'));
      if (bid > currentBid) {
        delta = {};
        delta[viewerId] = bid;
        state.submitDelta(delta);
      }
    }

    function renderInfo() {
      if (!wave.getState()) {
        return;
      }
      var highestBid = 0;
      var highestBidderId = null;
      var state = wave.getState();
      var keys = state.getKeys();
      for (var i = 0; i < keys.length; ++i) {
        var bidder = keys[i];
        var bid = parseInt(state.get(bidder));
        if (bid > highestBid) {
          highestBid = bid;
          highestBidderId = bidder;
        }
      }
      var bidderName = 'Nobody';
      var thumbNail = 'http://wave-api.appspot.com/public/unknown.gif';
      if (highestBidderId) {
        bidderName = highestBidderId;
        var participants = wave.getParticipants();
        if (participants) {
          for (var i = 0; i < participants.length; ++i) {
            if (participants[i].getId() == highestBidderId) {
              var highestBidder = participants[i];
              bidderName = highestBidder.getDisplayName();
              if (!bidderName) {
                bidderName = highestBidder.getId();
              }
              thumbNail = highestBidder.getThumbnailUrl();
            }
          }
        }
      }
      document.getElementById('bidderThumbnail').src = thumbNail;
      document.getElementById('bidderName').firstChild.nodeValue = bidderName;
      document.getElementById('highestBid').firstChild.nodeValue = highestBid;
      document.getElementById('yourBid').value = highestBid;
    }

    function main() {
      if (wave && wave.isInWaveContainer()) {
        wave.setStateCallback(renderInfo);
        wave.setParticipantCallback(renderInfo);
      }
    }
    gadgets.util.registerOnLoadHandler(main);
  </script>
  <img id="bidderThumbnail" src="http://wave-api.appspot.com/public/gadgets/unknown.gif" width="50" height="50"/><br/>
  <span id="bidderName">Nobody</span><br/>
  Highest bid: <span id="highestBid">0</span><br/>
  Your bid: <input id="yourBid" size="5" value="0"><button id="butCount" onclick="buttonClicked()">Bid</button><br/>
]]>
</Content>
</Module>