var emailFrame = document.getElementById("email-frame"); if (emailFrame) { // Resize the frame with its content var resizeFrame = function() { emailFrame.style.height = emailFrame.contentWindow.document.documentElement.scrollHeight + "px"; }; emailFrame.addEventListener("load", resizeFrame); emailFrame.contentWindow.addEventListener("resize", resizeFrame); // Polyfill in case the srcdoc attribute isn't supported if (!emailFrame.srcdoc) { var srcdoc = emailFrame.getAttribute("srcdoc"); var doc = emailFrame.contentWindow.document; doc.open(); doc.write(srcdoc); doc.close(); } }