HTTP header to detect a preload request by Google Chrome

Question

Google Chrome 17 introduced a new feature which preloads a webpage to improve rendering speed upon actually making the request (hitting enter in the omnibar).

Two qu

Answer 1

When Firefox pre-fetches content (at the behest of the referrer page’s markup), it sends the following header with the request: X-moz: prefetch

Safari does similarly, using: X-Purpose: preview. According to this ticket , Chrome does, too.

For pre-rendering, Chrome does not send any header whatsoever to the client. Instead, one must use the Page Visibility API, in JS

source, additional reading