[1] Issue 58459 - chromium - Add X-Purpose header to prefetch requests - An open-source project to help move the web forward. - Google Project Hosting ( 版) <https://code.google.com/p/chromium/issues/detail?id=58459>
[2] Issue 91735 - chromium - X-Purpose sent as "preview" not "instant" despite what documentation says, conflicts with Opera's use of X-Purpose: preview - An open-source project to help move the web forward. - Google Project Hosting ( 版) <https://code.google.com/p/chromium/issues/detail?id=91735>
[3] Google Chrome ( 版) <http://web.archive.org/web/20120116184139/http://www.google.com/chrome/intl/en/webmasters-faq.html#instant>
If a Google Chrome user has enabled the "Chrome Instant" feature, most webpages will load as soon as the URL has been typed into the address bar, before the user hits Enter.
If you are a website administrator, you can prevent Google Chrome from exhibiting this behavior on your website:
When Google Chrome makes the request to your website server, it will send the following header:
X-Purpose: instant
Detect this, and return an HTTP 403 ("Forbidden") status code.
When Google Chrome receives this status code, it will add your website to a blacklist maintained on the client. This blacklist will last the duration of that user’s browsing session.
[4] Enable Chrome Instant - Google Chrome Help ( 版) <http://web.archive.org/web/20120123055654/http://support.google.com/chrome/bin/answer.py?hl=en&answer=177873>
The Instant feature can help you search and browse faster on the web by showing search results in the browser window as you type in the address bar, even before you press Enter. If you don't see the results you want, just keep typing and the results dynamically update.
[5] Make your site shine in Speed Dial - Dev.Opera ( 版) <https://rawgit.com/operasoftware/devopera-static-backup/master/http/dev.opera.com/articles/view/opera-speed-dial-enhancements/index.html#with-x-purpose>
It's also possible to serve a different URL for your Speed Dial entry. This is because every Speed Dial request includes an additional X-Purpose: preview header.