Google Announced Prerender or Instant Page feature for entire web which Chrome users will benefit the most with perfecting and web acceleration built into it.
So what is Instant Page Feature ?
Though this is not something new and I have seen toolbar like Stumbleupon already doing it so when you click on the stumble button again, the next page loads very very fast. Since Stumble knows which link will get loaded when user clicks, it is easy for them.
Coming back to Google and Specifically to Google Search, They say Google will preload the web pages in their search result while you are still scanning through it. So when you actually click, the webpage gets loaded instantly.
Here is a video demo :
So here, Google Asked Chrome to Prerender some of the pages which they think user is likely to click.
How do a Webmaster asks Chrome for Prerendering / Prefetch ?
Chrome checks for a directive, specifically an HTML tag <link> with directive as rel=”prerender” in a webpage. If a page has that tag, Chrome will pre-render it.
So it should look like < link rel=”prerender” href=”example.com/mynextpage”/>
This indirectly also means that if some other page has asked to prerender a page on your site, Chrome can take a decision on doing that too.
So this means, I can get my whole website Prefetched ?
Good question and Google did thought about it and allowing it will possibly create trouble for end users when it comes to bandwidth cap.
- Chrome will only prerender at max one URL per instance of Chrome
- In case there are multiple prerender instructions, It is not defined which will be taken and why.
So the base rule is, Only Instruct links which you either feel is going to be clicked or are the most important.
Prerendering is not Guaranteed and for which type of webpages it will fail or abort
- In case users has disabled this feature in Chrome
- If the request is happening too often i.e. The time limit is set to within the last 500 ms.
- The url downloads a file
- You have video or audio in the page.
- Secure Pages
- Popup Windows Creation
- If the page is taking high resource
Analyzing the list above, the base rules seems to be for light pages and possibly for pages which provide good user experience. As many webmaster use combination of Video in their pages, prerender will not work that well for them and if you have annoying popups i.e. Asking users to subscribe as soon as the site loads, you will not be able to take advantage of this feature.
You can read more details on the Prerender FAQ for Developers