nexus4bot.js

/*
 * This Scratchpad will poll the Google Play Store every hour and
 * look for the words "Sold Out" in their banner div. If they're
 * not there, you'll get an alert that it's in!
 *
 * This Scratchpad needs to run in Browser Context!
 * https://developer.mozilla.org/en-US/docs/Tools/Scratchpad#Using_Scratchpad_to_access_Firefox_internals
 */

var duration = 1000 * 60 * 60; // ms * sec * min = 1 hour

var promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
                              .getService(Components.interfaces.nsIPromptService);

var URL = "https://play.google.com/store/devices/details?id=nexus_4_16gb";

// find our tab
var tab = gBrowser.browsers.filter(function (browser) {
  return browser.contentDocument.location.href == URL;
})[0];

// open if necessary
if (!tab) {
  gBrowser.selectedTab = gBrowser.addTab(URL);
  var tab = gBrowser.selectedBrowser; // grab the browser element
}

// create an nsIWebProgressListener to track state change
var listener = {
  QueryInterface: function(aIID) {
     if (aIID.equals(Components.interfaces.nsIWebProgressListener) ||
         aIID.equals(Components.interfaces.nsISupportsWeakReference) ||
         aIID.equals(Components.interfaces.nsISupports))
       return this;
     throw Components.results.NS_NOINTERFACE;
  },
  runCount: 0,
  onStateChange: function _onStateChange(aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
    // we're stopped, we should have what we need
    listener.runCount++;
    if (aStateFlags && Ci.nsIWebProgressListener.STATE_STOP) {
      tab.removeProgressListener(listener);
      let node = tab.contentDocument.querySelector("div.doc-banner-container");
      if (node && !/Sold out/.test(node.innerHTML))
        promptService.alert(this, "Surprise!", "It's Here!");
      else
        window.setTimeout(tester, duration);
    }
  }
};

function tester() {
  tab.addProgressListener(listener, Ci.nsIWebProgress.NOTIFY_STATE_WINDOW);
  tab.reload();
}

let timeout = window.setTimeout(tester, 0);