Instant Pages rolled out at a media event in San Francisco on June 14, 2011, makes use of prerendering technology in Chrome to make your site appear to load instantly in some cases, with no need for any extra work on your part.
Google says since its release they've been closely watching performance and listening to webmaster feedback, and since then Instant Pages has saved more than a thousand years of users' time. With those results in mind, the company will be gradually increasing how often they trigger the feature.
"In the vast majority of cases, webmasters don't have to do anything for their sites to work correctly with prerendering. As mentioned earlier, search traffic will be measured in Webmaster Tools just like before this feature: only results the user visits will be counted," posted Ziga Mahkovec, Software Engineer, Instant Pages.
Here is a look at a normal Google query vs. a Google query using Instant Pages:
A search query breakdown:
"If your site keeps track of pageviews on its own, you might be interested in the Page Visibility API, which allows you to detect when prerendering is occurring and factor those out of your statistics."
"If you use an ads or analytics package, check with them to see if their solution is already prerender-aware; if it is, in many cases you won't need to make any changes at all," Hahkovec adds.
Prerendering in Chrome is triggered by a
<link>tag in HTML, similar to how prefetching is triggered in Firefox. (Note, however, that unlike in Firefox the meta-http and HTTP header triggering methods are not supported at this time.) You can trigger prerendering of your web site by inserting a link element with a rel of "prerender", for example:
<link rel="prerender" href="http://example.org/index.html">
To check whether prerendering is happening for a page:
- Open Chrome's Task Manager.
- Load the page that includes the prerender hint.
- Check for a new line starting with "Prerender: " that shows a special icon (see the following screenshot). If you see such a line, prerendering is happening for that page.
Starting with Chrome 14, the net-internals tab includes more detailed information about prerendering. You can get to the net-internals tab by copying and pasting the following URL into the Chrome address bar: chrome://net-internals/#prerender
Prerender is currently enabled for many users of Chrome 13 by default. However, there are some cases where prerender may be disabled. This test page will alert you if prerendering appears to be disabled for you. To completely ensure that prerendering is enabled:
- Visit Chrome's settings and ensure that "Predict network actions to improve page load performance" is checked (it is checked by default).
- Start up Chrome with the
For more information on triggering Chrome's prerendering within your own site, see the Prerendering in Chrome article.
Here's a video of it in action: