Link prefetching is a browser mechanism, which utilizes browser idle time to download or prefetch documents that the user might visit in the near future. A web page provides a set of prefetching hints to the browser, and after the browser is finished loading the page, it begins silently prefetching specified documents and stores them in its cache. When the user visits one of the prefetched documents, it can be served up quickly out of the browser’s cache.
The browser looks for either an HTML tag or an HTTP Link: header with a relation type of either next or prefetch.
Google automatically instructs your browser to start downloading the top search result before you click on it. If you click on top result, the destination page will load faster than before.
Google uses a special prefetching feature in Firefox and Mozilla web browsers. Link prefetching is not available in Internet Explorer or other web browsers.
Why should you be concerned?
- You may end up with cookies and web pages in your web browser’s cache from web sites that you did not click on since prefetching happens automatically when you view Google search results pages. You can delete these files by clearing your browser’s cache and cookies.
- Because the prefetch request will happen whether or not the user clicks on the result, so it may result in additional traffic to your web server.
Webmaster-specific information about how to deal with this feature is here.
How to disable prefetching?
You can disable prefetching in your web browser preferences, as described in the Mozilla Prefetching FAQ. In Firefox, you can disable prefetching by doing the following:
- Type “about:config” the address bar.
- Scroll down to the setting “network.prefetch-next” and set the value to “False”.