iframe.js

        $(document).ready(function() {
          if(window.self !== window.top) {
            var currentHeight = document.body.clientHeight;
            var resizeIframeTracker = setInterval(function() {
              var height = document.body.clientHeight;
              if(currentHeight !== height) {
                message = JSON.stringify({"frameHeight": height})
                window.parent.postMessage(message, "*");
                currentHeight = height;
              }
            }, 500)
          }
        });