iframe.js

(function($) {

  //console.log('in iframe.js');

  // If the iframe preloader did not find an iframe, return immediately
  //
  if ($(".sgr_iframe").length <= 0) {
    //debug("no sgr_iframe exists for " + self.location.href);
    return;
  }
  //debug("** sgr_iframe exists for " + self.location.href);


  // If this is the google reader settings iframe, return
  //
  if (self.location.href.match(/\/\/(www\.|)google\.com\/reader\/settings/)) {
    //debug("in greader settings iframe, returning");
    return;
  }

  // Minimum allowed iframe height to be sent to the parent
  //
  const MIN_IFRAME_HEIGHT = 700;

  // Maximum allowed times to send height to parent.
  //
  const MAX_SEND_SIZE = 25;

  // Counter for amount of times height has been sent to parent.
  var send_size_counter = 0;


  // Execute the posting of a message to our parent window.
  //
  function sendMessageToParent(msg) {
    if (chrome) {
      var iframe_id = document.getElementsByClassName("sgr_iframe")[0].innerText;
      if (iframe_id) {
        chrome.extension.sendRequest({action: "window_height", window_height: msg, iframe_id: iframe_id}, function(response) {
          //debug("iframe.js: " + response.action + " - " + response._msg);
        });
      }
    }
  }


  // Find the height of the window and send it to the parent window.
  // This is done via parent.postMessage()
  //
  function sendSizeToParent() {

    //debug('sendSizeToParent()');

    // Check if we have exceeded the maximum allowed times to send the height to the parent.
    // This is here as a catchall or precaution in case we get stuck in a resize loop and continually
    // spam the parent with height values. This can sometimes occur if we use a window resize event 
    // handler to determine when to send height to the parent.
    //
    if (send_size_counter > MAX_SEND_SIZE) {
      //debug("sendSizeToParent() exceeded call limit");
      if (jQuery) {
        $(window).unbind('resize', sendSizeToParent);
      }
      return false;
    }

    try {
      var scroll_height = document.body.scrollHeight;
    } catch(e) {
      debug("document.body.scrollHeight not found");
      return false;
    }

    send_size_counter += 1;

    var height;

    // If jQuery has loaded, use it to find the window height
    //
    if (jQuery) { 
      // document.body.scrollHeight *seems* to be the correct height to use in 
      // cases where a page has been shortened in height during it's load process. 
      // So if document.body.scrollHeight is less than $(document).height(), but 
      // still larger than the minimum allowable iframe height, use it.
      //
      if (scroll_height < $(document).height() && scroll_height > MIN_IFRAME_HEIGHT) {
        // Add a little fudge (20px) to cover fringe cases of incorrect height
        //
        height = scroll_height + 20;
      } else {
        height = $(document).height();
      }

    // If we don't have access to jQuery, simply use document.body.scrollHeight
    //
    } else {
      // Add a little fudge (20px) to cover fringe cases of incorrect height
      //
      height = scroll_height + 20;
    }

    // Send the height to the parent using postMessage()
    //
    sendMessageToParent(height);

    return false;
  }

  // MAIN
  //

  // Send the window size to the parent right now
  //
  //debug("immediate sendSizeTOParent " + self.location.href);
  sendSizeToParent();


  $(document).ready(function() {
    //debug("document.ready sendSizeTOParent " + self.location.href);
    sendSizeToParent();
  });

  // Send the window size to the parent after the window has loaded
  //
  $(window).load(function() {
    //debug("window.load sendSizeTOParent " + self.location.href);
    sendSizeToParent();
  });

})(jQuery);