What is the critical rendering path?

• It is the series of events that must take place to render (display) the initial view of a webpage.
• Example: get html > get resources > parse > display webpage

CSS

• No more than one external CSS stylesheet of an reasonable size (less than 75k or so)
• Inline small CSS into HTML using style tags for above the fold content
• No @import calls for CSS
• No CSS in HTML things like your divs or your h1s (in element CSS)

Javascript

removing blocking javascript

<script type="text/javascript">

function downloadJSAtOnload() {
    var element = document.createElement("script");
    element.src = "defer.js";
    document.body.appendChild(element);
}
if (window.addEventListener)
    window.addEventListener("load", downloadJSAtOnload, false);
else if (window.attachEvent)
    window.attachEvent("onload", downloadJSAtOnload);
else window.onload = downloadJSAtOnload;

</script>