167:
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requests are said to be "safe", i.e., a user agent that issues one of these requests should expect that the request results in no change on the recipient server. However, it is common for website operators to use these requests outside of this constraint. Plain hyperlinks (which almost universally
521:
Similarly, it is entirely possible for a hosting service to provide a Web front end to manage files, including links that delete one or more files. Users who visit pages containing these types of links, (whilst using a browser which employs an indiscriminate link prefetcher), might find that they
518:
result in GET requests) are often used to implement logout functionality and account verification, e.g., when a user completes an account creation form, and an automated service sends a verification e-mail to the user's given e-mail address.
483:
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
152:
Link: <//pagead2.googlesyndication.com>; rel=dns-prefetch, </js/bootstrap.min.js>; as=script; rel=preload, </ads.html>; rel=prerender, </css/bootstrap.min.css>; as=style; rel=preload
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Users and website operators who pay for the amount of bandwidth they use find themselves paying for traffic for pages the user might not actually visit, and advertisers might pay for viewed ads on sites that are never
791:
476:
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.
457:
As of version 11, Internet
Explorer supports the following set of features to expand its prefetching capabilities: "prerender", "dns-prefetch" and "lazyload" (images only).
573:
In the case of mobile devices or for users with a limited bandwidth allowance, prefetching may result in an unnecessary costly drain on limited bandwidth.
994:
29:
Prefetching is accomplished through hints in web pages. These hints are used by the browser to prefetch links. Resources which can be prefetched include:
795:
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warns that improper use may result in the aforementioned increased bandwidth usage, slower loading of other links, and slightly stale content.
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22:
allows web browsers to pre-load resources. This speeds up both the loading and rendering of web pages. Prefetching was first introduced in
890:
201:
186:
Please help improve this article by looking for better, more reliable sources. Unreliable citations may be challenged and removed.
956:
562:
Users may be exposed to more security risks by downloading more pages, or from un-requested sites (additionally compounded as
525:
Additionally, there are a number of criticisms regarding the privacy and resource usage implications of link prefetching:
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Users may violate acceptable-use policies of their network or organization if prefetching accesses unauthorized content.
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It is possible for implementations to prefetch links even when they are not specified as prefetch links.
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Hints to the browser. Common hints include DNS queries, opening TCP connections, and page pre-rendering.
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may become less reliable due to registering page hits that were never seen by the user.
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An issue inherent to indiscriminate link prefetching involves the misuse of "safe"
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supports prefetching of linked web content by "prerendering", as of version
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has employed the use of prefetching and preloading since the release of
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A WordPress plugin that implements the true dynamic prerender meta tag
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396:
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23:
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are the first referenced browsers to support link prefetching.
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have been logged out or that their files have been deleted.
57:
There are two W3C standards covering prefetching for HTML5:
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proxy appliance is known to use non‑compliant prefetching.
113:<link rel="dns-prefetch" href="http://example.com/">
99:<link rel="prefetch" href="http://www.example.com/">
865:
863:
825:"Link Prefetching in Mozilla: A Server-Driven Approach"
1036:
Prerender and prefetch support in
Internet Explorer 11
891:"Internet Explorer 9 Network Performance Improvements"
544:
merely because a malware-spreading link is prefetched.
127:<link rel="prerender" href="/page/to/prerender">
551:
Web statistics such as browser usage, search engine
97:
Standard link prefetch (supported by most browsers):
871:"Web Developer's Guide to Prerendering in Chrome"
792:"Getting to the Content You Want, Faster in IE11"
406:(discontinued product, may technically be called
49:connections can also be hinted for prefetching.
810:"Bug 730101 - Implement prerendering in Firefox"
529:Cookies set or sent to third parties compromise
794:. IEBlog, Microsoft. 2013-12-04. Archived from
64:Hints to specific URLs. Common hints include
8:
430:supports DNS prefetching, as of version 3.5.
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446:supports prefetching of IP addresses by "
202:Learn how and when to remove this message
16:Allows web browsers to pre-load resources
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7:
959:. p. 50. sec. 9.1.1.
952:Hypertext Transfer Protocol—HTTP/1.1
636:
634:
609:
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137:<img src="image.jpg" lazyload>
566:become more advanced and diverse).
14:
713:Resource Hints: W3C Working Draft
941:; Masinter, Larry; Leach, Paul;
165:
823:Fisher, Darin; Saksena, Gagan.
536:Enables essentially/borderline
464:Popular sites using prefetching
1:
848:"Controlling DNS prefetching"
579:In the case of prerendering,
1026:Mozilla Link Prefetching FAQ
769:. Steve Souders. 2013-10-07.
709:"Resource Hints (Example 6)"
93:methods for prefetch hints:
1056:Hypertext Transfer Protocol
450:prefetching", as of version
37:, image, audio, video, and
1072:
1031:Test for Prefetch support
955:. Network Working Group.
540:malware installation via
393:Mozilla Application Suite
226:Standard link prefetching
219:
216:
665:Nottingham, M. (2010).
472:is the most well-known
174:Some of this article's
911:"About Google Instant"
812:. Mozilla. 2014-10-18.
404:Google Web Accelerator
220:Prefetching Supported
995:"Mouseover Prefetch?"
501:Issues and criticisms
131:Lazy-load of images (
494:Internet Explorer 11
117:Page pre-rendering (
53:Prefetching in HTML5
997:. Gervase Markham,
937:; Mogul, Jeffrey;
564:drive-by downloads
241:Lazy-load (Images)
593:Cache prefetching
538:Zero-click attack
444:Internet Explorer
402:Browsing using a
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306:Internet Explorer
212:
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133:Internet Explorer
123:Internet Explorer
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1001:. Archived from
993:various (2009).
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966:10.17487/RFC2616
943:Berners-Lee, Tim
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642:"Resource Hints"
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148:: Example below.
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20:Link prefetching
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496:(October 2013).
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428:Mozilla Firefox
424:
422:Modern browsers
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325:Mozilla Firefox
231:DNS prefetching
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157:Browser support
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105:Mozilla Firefox
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81:Resource hints
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1020:External links
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947:"Safe Methods"
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798:on 2014-05-12.
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479:Specifically,
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176:listed sources
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111:, and others):
103:DNS prefetch (
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1005:on 2009-05-31
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948:
945:(June 1999).
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931:Fielding, Roy
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767:"Prebrowsing"
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667:"Web Linking"
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646:w3c.github.io
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619:w3c.github.io
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434:Google Chrome
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119:Google Chrome
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109:Google Chrome
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83:
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72:, images and
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61:Link preload
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36:
32:
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25:
21:
1007:. Retrieved
1003:the original
988:
977:. Retrieved
951:
925:
914:. Retrieved
905:
894:. Retrieved
885:
874:. Retrieved
851:. Retrieved
842:
831:. Retrieved
818:
804:
796:the original
717:. Retrieved
712:
703:
692:. Retrieved
670:
660:
649:. Retrieved
645:
622:. Retrieved
618:
578:
575:
572:
524:
520:
507:HTTP methods
504:
236:Prerendering
198:
189:
178:
146:HTTP headers
125:and others):
89:
56:
28:
19:
18:
999:MozillaZine
935:Gettys, Jim
531:Web privacy
179:may not be
1009:2009-12-16
979:2009-12-16
916:2014-05-09
896:2014-05-09
876:2014-05-09
853:2014-05-09
833:2014-05-09
719:2016-10-31
694:2016-03-19
651:2016-03-19
624:2016-03-19
599:References
408:precaching
383:Historical
66:JavaScript
45:names and
31:JavaScript
615:"Preload"
557:page hits
553:referrers
415:Blue Coat
192:July 2021
74:web fonts
39:web fonts
1050:Category
673:. IETF.
671:RFC 5988
587:See also
548:visited.
511:HTTP GET
268:Chromium
250:browser
217:Browser
181:reliable
484:engine.
474:website
248:Android
689:367264
687:
581:Google
555:, and
509:. The
481:Google
470:Google
452:
438:
395:, and
363:Safari
828:(PDF)
715:. W3C
685:S2CID
397:WebTV
344:Opera
91:HTML5
24:HTML5
974:2616
957:IETF
542:0day
515:HEAD
513:and
490:Bing
413:The
389:iCab
370:Yes
348:Yes
332:Yes
329:Yes
319:Yes
316:Yes
313:Yes
310:Yes
297:Yes
294:Yes
291:Yes
278:Yes
275:Yes
272:Yes
253:Yes
144:for
142:Link
971:RFC
961:doi
675:doi
454:9.
448:DNS
440:11.
376:No
373:No
367:No
357:No
354:No
351:No
338:No
335:No
300:No
281:No
262:No
259:No
256:No
70:CSS
47:TCP
43:DNS
35:CSS
26:.
1052::
969:.
949:.
933:;
862:^
775:^
728:^
711:.
683:.
669:.
644:.
633:^
617:.
606:^
391:,
135:):
121:,
107:,
68:,
41:.
33:,
1012:.
982:.
963::
919:.
899:.
879:.
856:.
836:.
722:.
697:.
677::
654:.
627:.
533:.
410:)
205:)
199:(
194:)
190:(
184:.
76:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
