code bit to observe changes in DOM. Based on http://stackoverflow.com/a/18970264

MutationObserver.js

var whatToObserve = {childList: true, attributes: true, subtree: true, attributeOldValue: true, attributeFilter: ['class', 'style']};
var mutationObserver = new MutationObserver(function(mutationRecords) {
  $.each(mutationRecords, function(index, mutationRecord) {
    if (mutationRecord.type === 'childList') {
      if (mutationRecord.addedNodes.length > 0) {
        //DOM node added, do something
        console.log("DOM node added");
      }
      else if (mutationRecord.removedNodes.length > 0) {
        //DOM node removed, do something
        console.log("DOM node removed");
      }
    }
    else if (mutationRecord.type === 'attributes') {
      if (mutationRecord.attributeName === 'class') {
        //class changed, do something
        console.log("class changed");
      }
    }
  });
});
mutationObserver.observe(document.body, whatToObserve);