178:
528:
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
532:
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
529:
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.
494:
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
163:
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
558:
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
802:
487:
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.
468:
As of version 11, Internet
Explorer supports the following set of features to expand its prefetching capabilities: "prerender", "dns-prefetch" and "lazyload" (images only).
584:
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.
1005:
40:
Prefetching is accomplished through hints in web pages. These hints are used by the browser to prefetch links. Resources which can be prefetched include:
806:
594:
warns that improper use may result in the aforementioned increased bandwidth usage, slower loading of other links, and slightly stale content.
1066:
33:
allows web browsers to pre-load resources. This speeds up both the loading and rendering of web pages. Prefetching was first introduced in
901:
212:
197:
Please help improve this article by looking for better, more reliable sources. Unreliable citations may be challenged and removed.
967:
573:
Users may be exposed to more security risks by downloading more pages, or from un-requested sites (additionally compounded as
536:
Additionally, there are a number of criticisms regarding the privacy and resource usage implications of link prefetching:
57:
191:
580:
Users may violate acceptable-use policies of their network or organization if prefetching accesses unauthorized content.
186:
258:
403:
1013:
236:
949:
591:
491:
480:
414:
278:
177:
80:
45:
587:
It is possible for implementations to prefetch links even when they are not specified as prefetch links.
719:
95:
Hints to the browser. Common hints include DNS queries, opening TCP connections, and page pre-rendering.
858:
981:
504:
500:
373:
1046:
1036:
881:
354:
921:
695:
458:
53:
418:
957:
603:
574:
548:
454:
425:
316:
143:
133:
971:
685:
777:
953:
438:
335:
241:
115:
1051:
570:
may become less reliable due to registering page hits that were never seen by the user.
84:
49:
820:
1060:
563:
444:
297:
129:
119:
941:
516:
An issue inherent to indiscriminate link prefetching involves the misuse of "safe"
251:
246:
156:
699:
1009:
984:
961:
541:
517:
17:
945:
76:
41:
567:
525:
447:
supports prefetching of linked web content by "prerendering", as of version
1041:
835:
521:
652:
503:
has employed the use of prefetching and preloading since the release of
484:
1052:
A WordPress plugin that implements the true dynamic prerender meta tag
677:
976:
690:
407:
101:
34:
625:
552:
399:
410:
are the first referenced browsers to support link prefetching.
171:
533:
have been logged out or that their files have been deleted.
68:
There are two W3C standards covering prefetching for HTML5:
428:
proxy appliance is known to use non‑compliant prefetching.
124:<link rel="dns-prefetch" href="http://example.com/">
110:<link rel="prefetch" href="http://www.example.com/">
876:
874:
836:"Link Prefetching in Mozilla: A Server-Driven Approach"
1047:
Prerender and prefetch support in
Internet Explorer 11
902:"Internet Explorer 9 Network Performance Improvements"
555:
merely because a malware-spreading link is prefetched.
138:<link rel="prerender" href="/page/to/prerender">
562:
Web statistics such as browser usage, search engine
108:
Standard link prefetch (supported by most browsers):
882:"Web Developer's Guide to Prerendering in Chrome"
803:"Getting to the Content You Want, Faster in IE11"
417:(discontinued product, may technically be called
60:connections can also be hinted for prefetching.
821:"Bug 730101 - Implement prerendering in Firefox"
540:Cookies set or sent to third parties compromise
805:. IEBlog, Microsoft. 2013-12-04. Archived from
75:Hints to specific URLs. Common hints include
8:
441:supports DNS prefetching, as of version 3.5.
797:
795:
793:
791:
789:
787:
772:
770:
768:
766:
764:
762:
760:
224:
975:
758:
756:
754:
752:
750:
748:
746:
744:
742:
740:
689:
457:supports prefetching of IP addresses by "
213:Learn how and when to remove this message
27:Allows web browsers to pre-load resources
614:
7:
970:. p. 50. sec. 9.1.1.
963:Hypertext Transfer Protocol—HTTP/1.1
647:
645:
620:
618:
148:<img src="image.jpg" lazyload>
577:become more advanced and diverse).
25:
724:Resource Hints: W3C Working Draft
952:; Masinter, Larry; Leach, Paul;
176:
834:Fisher, Darin; Saksena, Gagan.
547:Enables essentially/borderline
475:Popular sites using prefetching
1:
859:"Controlling DNS prefetching"
590:In the case of prerendering,
1037:Mozilla Link Prefetching FAQ
780:. Steve Souders. 2013-10-07.
720:"Resource Hints (Example 6)"
104:methods for prefetch hints:
1067:Hypertext Transfer Protocol
461:prefetching", as of version
48:, image, audio, video, and
1083:
1042:Test for Prefetch support
966:. Network Working Group.
551:malware installation via
404:Mozilla Application Suite
237:Standard link prefetching
230:
227:
676:Nottingham, M. (2010).
483:is the most well-known
185:Some of this article's
922:"About Google Instant"
823:. Mozilla. 2014-10-18.
415:Google Web Accelerator
231:Prefetching Supported
1006:"Mouseover Prefetch?"
512:Issues and criticisms
142:Lazy-load of images (
505:Internet Explorer 11
128:Page pre-rendering (
64:Prefetching in HTML5
1008:. Gervase Markham,
948:; Mogul, Jeffrey;
575:drive-by downloads
252:Lazy-load (Images)
604:Cache prefetching
549:Zero-click attack
455:Internet Explorer
413:Browsing using a
391:
390:
317:Internet Explorer
223:
222:
215:
144:Internet Explorer
134:Internet Explorer
16:(Redirected from
1074:
1025:
1024:
1022:
1021:
1012:. Archived from
1004:various (2009).
1001:
995:
994:
992:
991:
979:
977:10.17487/RFC2616
954:Berners-Lee, Tim
938:
932:
931:
929:
928:
918:
912:
911:
909:
908:
898:
892:
891:
889:
888:
878:
869:
868:
866:
865:
855:
849:
848:
846:
845:
840:
831:
825:
824:
817:
811:
810:
799:
782:
781:
774:
735:
734:
732:
731:
716:
710:
709:
707:
706:
693:
691:10.17487/RFC5988
673:
667:
666:
664:
663:
653:"Resource Hints"
649:
640:
639:
637:
636:
622:
464:
450:
225:
218:
211:
207:
204:
198:
180:
172:
159:: Example below.
154:
149:
139:
125:
111:
31:Link prefetching
21:
1082:
1081:
1077:
1076:
1075:
1073:
1072:
1071:
1057:
1056:
1033:
1028:
1019:
1017:
1003:
1002:
998:
989:
987:
950:Frystyk, Henrik
940:
939:
935:
926:
924:
920:
919:
915:
906:
904:
900:
899:
895:
886:
884:
880:
879:
872:
863:
861:
857:
856:
852:
843:
841:
838:
833:
832:
828:
819:
818:
814:
801:
800:
785:
776:
775:
738:
729:
727:
718:
717:
713:
704:
702:
675:
674:
670:
661:
659:
651:
650:
643:
634:
632:
624:
623:
616:
612:
600:
514:
507:(October 2013).
477:
462:
448:
439:Mozilla Firefox
435:
433:Modern browsers
396:
336:Mozilla Firefox
242:DNS prefetching
219:
208:
202:
199:
196:
181:
170:
168:Browser support
165:
152:
147:
137:
123:
116:Mozilla Firefox
109:
92:Resource hints
66:
28:
23:
22:
18:DNS prefetching
15:
12:
11:
5:
1080:
1078:
1070:
1069:
1059:
1058:
1055:
1054:
1049:
1044:
1039:
1032:
1031:External links
1029:
1027:
1026:
996:
958:"Safe Methods"
933:
913:
893:
870:
850:
826:
812:
809:on 2014-05-12.
783:
736:
711:
668:
641:
613:
611:
608:
607:
606:
599:
596:
582:
581:
578:
571:
560:
556:
545:
513:
510:
509:
508:
498:
497:
496:
490:Specifically,
476:
473:
472:
471:
470:
469:
452:
442:
434:
431:
430:
429:
422:
411:
395:
392:
389:
388:
385:
382:
379:
376:
370:
369:
366:
363:
360:
357:
351:
350:
347:
344:
341:
338:
332:
331:
328:
325:
322:
319:
313:
312:
309:
306:
303:
300:
294:
293:
290:
287:
284:
281:
275:
274:
271:
268:
265:
262:
255:
254:
249:
244:
239:
233:
232:
229:
221:
220:
187:listed sources
184:
182:
175:
169:
166:
162:
161:
160:
150:
140:
126:
122:, and others):
114:DNS prefetch (
112:
99:
98:
97:
96:
90:
89:
88:
65:
62:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1079:
1068:
1065:
1064:
1062:
1053:
1050:
1048:
1045:
1043:
1040:
1038:
1035:
1034:
1030:
1016:on 2009-05-31
1015:
1011:
1007:
1000:
997:
986:
983:
978:
973:
969:
965:
964:
959:
956:(June 1999).
955:
951:
947:
943:
942:Fielding, Roy
937:
934:
923:
917:
914:
903:
897:
894:
883:
877:
875:
871:
860:
854:
851:
837:
830:
827:
822:
816:
813:
808:
804:
798:
796:
794:
792:
790:
788:
784:
779:
778:"Prebrowsing"
773:
771:
769:
767:
765:
763:
761:
759:
757:
755:
753:
751:
749:
747:
745:
743:
741:
737:
725:
721:
715:
712:
701:
697:
692:
687:
683:
679:
678:"Web Linking"
672:
669:
658:
657:w3c.github.io
654:
648:
646:
642:
631:
630:w3c.github.io
627:
621:
619:
615:
609:
605:
602:
601:
597:
595:
593:
588:
585:
579:
576:
572:
569:
565:
561:
557:
554:
550:
546:
543:
539:
538:
537:
534:
530:
527:
523:
519:
511:
506:
502:
499:
493:
489:
488:
486:
482:
479:
478:
474:
467:
466:
460:
456:
453:
446:
445:Google Chrome
443:
440:
437:
436:
432:
427:
423:
420:
416:
412:
409:
405:
401:
398:
397:
393:
386:
383:
380:
377:
375:
372:
371:
367:
364:
361:
358:
356:
353:
352:
348:
345:
342:
339:
337:
334:
333:
329:
326:
323:
320:
318:
315:
314:
310:
307:
304:
301:
299:
298:Google Chrome
296:
295:
291:
288:
285:
282:
280:
277:
276:
272:
269:
266:
263:
260:
257:
256:
253:
250:
248:
245:
243:
240:
238:
235:
234:
226:
217:
214:
206:
194:
193:
188:
183:
179:
174:
173:
167:
158:
151:
145:
141:
135:
131:
130:Google Chrome
127:
121:
120:Google Chrome
117:
113:
107:
106:
105:
103:
94:
93:
91:
86:
83:, images and
82:
78:
74:
73:
72:Link preload
71:
70:
69:
63:
61:
59:
55:
51:
47:
43:
38:
36:
32:
19:
1018:. Retrieved
1014:the original
999:
988:. Retrieved
962:
936:
925:. Retrieved
916:
905:. Retrieved
896:
885:. Retrieved
862:. Retrieved
853:
842:. Retrieved
829:
815:
807:the original
728:. Retrieved
723:
714:
703:. Retrieved
681:
671:
660:. Retrieved
656:
633:. Retrieved
629:
589:
586:
583:
535:
531:
518:HTTP methods
515:
247:Prerendering
209:
200:
189:
157:HTTP headers
136:and others):
100:
67:
39:
30:
29:
1010:MozillaZine
946:Gettys, Jim
542:Web privacy
190:may not be
1020:2009-12-16
990:2009-12-16
927:2014-05-09
907:2014-05-09
887:2014-05-09
864:2014-05-09
844:2014-05-09
730:2016-10-31
705:2016-03-19
662:2016-03-19
635:2016-03-19
610:References
419:precaching
394:Historical
77:JavaScript
56:names and
42:JavaScript
626:"Preload"
568:page hits
564:referrers
426:Blue Coat
203:July 2021
85:web fonts
50:web fonts
1061:Category
684:. IETF.
682:RFC 5988
598:See also
559:visited.
522:HTTP GET
279:Chromium
261:browser
228:Browser
192:reliable
495:engine.
485:website
259:Android
700:367264
698:
592:Google
566:, and
520:. The
492:Google
481:Google
463:
449:
406:, and
374:Safari
839:(PDF)
726:. W3C
696:S2CID
408:WebTV
355:Opera
102:HTML5
35:HTML5
985:2616
968:IETF
553:0day
526:HEAD
524:and
501:Bing
424:The
400:iCab
381:Yes
359:Yes
343:Yes
340:Yes
330:Yes
327:Yes
324:Yes
321:Yes
308:Yes
305:Yes
302:Yes
289:Yes
286:Yes
283:Yes
264:Yes
155:for
153:Link
982:RFC
972:doi
686:doi
465:9.
459:DNS
451:11.
387:No
384:No
378:No
368:No
365:No
362:No
349:No
346:No
311:No
292:No
273:No
270:No
267:No
81:CSS
58:TCP
54:DNS
46:CSS
37:.
1063::
980:.
960:.
944:;
873:^
786:^
739:^
722:.
694:.
680:.
655:.
644:^
628:.
617:^
402:,
146:):
132:,
118:,
79:,
52:.
44:,
1023:.
993:.
974::
930:.
910:.
890:.
867:.
847:.
733:.
708:.
688::
665:.
638:.
544:.
421:)
216:)
210:(
205:)
201:(
195:.
87:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
