Link prefetching
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Link prefetching allows web browsers to pre-load resources. This speeds up both the loading and rendering of web pages. Prefetching was first introduced in HTML5. Prefetching is accomplished through hints in web pages. These hints are used by the browser to prefetch links. Resources which can be prefetched include: JavaScript, CSS, image, audio, video, and web fonts. DNS names and TCP connections can also be hinted for prefetching.
Link prefetching allows web browsers to pre-load resources. This speeds up both the loading and rendering of web pages. Prefetching was first introduced in HTML5. Prefetching is accomplished through hints in web pages. These hints are used by the browser to prefetch links. Resources which can be prefetched include: JavaScript, CSS, image, audio, video, and web fonts. DNS names and TCP connections can also be hinted for prefetching. Standard link prefetch (supported by most browsers): DNS prefetch (Mozilla Firefox, Google Chrome, and others) : Page pre-rendering (Google Chrome, Internet Explorer and others) : Lazy-load of images (Internet Explorer) : Link for HTTP headers: Example below. Link: ; rel=dns-prefetch, ; as=script; rel=preload, ; rel=prerender, ; as=style; rel=preload
Browser support
Historical
iCab, Mozilla Application Suite, and WebTV are the first referenced browsers to support link prefetching. Browsing using a Google Web Accelerator (discontinued product, may technically be called precaching) The Blue Coat proxy appliance is known to use non‑compliant prefetching.
Modern browsers
Mozilla Firefox supports DNS prefetching, as of version 3.5. Google Chrome supports prefetching of linked web content by "prerendering", as of version 11. Internet Explorer supports prefetching of IP addresses by "DNS prefetching", as of version 9. As of version 11, Internet Explorer supports the following set of features to expand its prefetching capabilities: "prerender", "dns-prefetch" and "lazyload" (images only).
Popular sites using prefetching
Google is the most well-known website that takes advantage of this feature so as to improve the user experience. If the first hit is considered very probable to be the desired hit, it is assigned as a prefetchable link. Specifically, Google implemented "Google Instant Pages" in August 2011 which takes advantage of the aforementioned feature, predictive search completion, and preloading search results as the user types in order to improve the performance of the search engine. Bing has employed the use of prefetching and preloading since the release of Internet Explorer 11 (October 2013).
See also
Cache prefetching
References
External links
Mozilla Link Prefetching FAQ Test for Prefetch support Prerender and prefetch support in Internet Explorer 11 A WordPress plugin that implements the true dynamic prerender meta tag
Text derived from https://en.wikipedia.org/w/index.php?oldid=1360096219 under CC BY-SA 4.0; modifications have been made.