I once did experiment in IE6 and Firefox 2.x. The F5 refresh would trigger a HTTP request sent to the VPS with an If-Modified-Since header, while Ctrl + F5 would not have sầu such a header. In my understanding, F5 will try lớn utilize cached content as much as possible, while Ctrl + F5 is intended to lớn abandon all cached content and just retrieve sầu all content from the servers again.
But today, I noticed that in some of the lademo browsers (Chrome, IE8) it doesn"t work in this way anymore. Both F5 và Ctrl + F5 sover the If-Modified-Since header.
So how is this supposed lớn work, or (if there is no standard) how vì chưng the major browsers differ in how they implement these refresh features?
http browser caching cross-browser refresh
Share
Follow
edited Atruyền thông quảng cáo 9 "16 at 9:51
Krzysztof Krasoń
23k1414 gold badges7777 silver badges9999 bronze badges
asked Dec 22 "08 at 2:00
Morgan ChengMorgan Cheng
65.6k6363 gold badges165165 silver badges223223 bronze badges
3
Add a bình luận |
6 Answers 6
Active sầu Oldest Votes
326
Generally speaking:
F5 may give sầu you the same page even if the nội dung is changed, because it may load the page from cađậy. But Ctrl-F5 forces a cache refresh, và will guarantee that if the content is changed, you will get the new nội dung.
Bạn đang xem: Ctrl f5 là gì
Share
Follow
edited Mar 11 "14 at 9:20
naXa
25.8k1414 gold badges153153 silver badges212212 bronze badges
answered Dec 22 "08 at 2:10
dancavallarodancavallaro
12.5k77 gold badges3333 silver badges3333 bronze badges
4
Add a phản hồi |
526
It is up to the browser but they behave sầu in similar ways.
I have tested FF, IE7, Opera and Chrome.
F5 usually updates the page only if it is modified. The browser usually tries to lớn use all types of cabịt as much as possible và adds an "If-modified-since" header to the request. Opera differs by sending a "Cache-Control: no-cache".
CTRL-F5 is used khổng lồ force an update, disregarding any cabít. IE7 adds an "Cache-Control: no-cache", as does FF, which also adds "Pragma: no-cache". Chrome does a normal "If-modified-since" và Opera ignores the key.
If I remember correctly it was Netscape which was the first browser khổng lồ add tư vấn for cache-control by adding "Pragma: No-cache" when you pressed CTRL-F5.
Xem thêm: Hướng Dẫn Tập Ngực Tại Nhà Hiệu Quả Ít Tốn Kém Nhất
Edit: Updated table
The table below is updated with information on what will happen when the browser"s refresh-button is clicked (after a request by Joel Coehoorn), & the "max-age=0" Cache-control-header.
Updated table, 27 September 2010
┌────────────┬───────────────────────────────────────────────┐│ UPDATED │ Firefox 3.x ││27 SEPhường 2010 │ ┌────────────────────────────────────────────┤│ │ │ MSIE 8, 7 ││ Version 3 │ │ ┌─────────────────────────────────────────┤│ │ │ │ Chrome 6.0 ││ │ │ │ ┌──────────────────────────────────────┤│ │ │ │ │ Chrome 1.0 ││ │ │ │ │ ┌───────────────────────────────────┤│ │ │ │ │ │ Opera 10, 9 ││ │ │ │ │ │ ┌────────────────────────────────┤│ │ │ │ │ │ │ │├────────────┼──┼──┼──┼──┼──┼────────────────────────────────┤│ F5│IM│I │IM│IM│C │ ││ SHIFT-F5│- │- │CP│IM│- │ Legend: ││ CTRL-F5│CP│C │CP│IM│- │ I = "If-Modified-Since" ││ ALT-F5│- │- │- │- │*2│ P = "Pragma: No-cache" ││ ALTGR-F5│- │I │- │- │- │ C = "Cache-Control: no-cache" │├────────────┼──┼──┼──┼──┼──┤ M = "Cache-Control: max-age=0" ││ CTRL-R│IM│I │IM│IM│C │ - = ignored ││CTRL-SHIFT-R│CP│- │CP│- │- │ │├────────────┼──┼──┼──┼──┼──┤ ││ Click│IM│I │IM│IM│C │ With "click" I refer khổng lồ a ││ Shift-Click│CP│I │CP│IM│C │ mouse cliông xã on the browsers ││ Ctrl-Click│*1│C │CP│IM│C │ refresh-ibé. ││ Alt-Click│IM│I │IM│IM│C │ ││ AltGr-Click│IM│I │- │IM│- │ │└────────────┴──┴──┴──┴──┴──┴────────────────────────────────┘Versions tested:
Firefox 3.1.6 and 3.0.6 (WINXP)MSIE 8.0.6001 & 7.0.5730.11 (WINXP)Chrome 6.0.472.63 and 1.0.151.48 (WINXP)Opera 10.62 & 9.61 (WINXP)Notes:
Version 3.0.6 sends I và C, but 3.1.6 opens the page in a new tab,making a normal request with only "I".
Version 10.62 does nothing. 9.61 might vày C unless it was a typo in my old table.
chú ý about Chrome 6.0.472: If you bởi vì a forced reload (like CTRL-F5) it behaves lượt thích the url is internally marked to always vì a forced reload. The flag is cleared if you go to lớn the address bar và press enter.