如何解决缓存提供的javascript文件的问题? [英] How to solve problem with javascript files served from cache?

问题描述

更新服务器端代码(与JavaScript相关)后，旧的JavaScript文件将从缓存中提供.

When server side code is updated (related to JavaScript) the old JavaScript files are served from cache.

我需要一个解决方案，将旧的JavaScript文件更新为新版本.服务器上的文件更新后，需要使浏览器缓存(与JavaScript相关)失效.

I need a solution where the old JavaScript files get updated to their newer versions. Browser cache (related to JavaScript) need to be invalidated once the files on server are updated.

对于这个问题，我有以下解决方案.

I have got the following solution to this problem.

var randomnumber=Math.floor(Math.random()*10000);

var scriptfile='http://www.whatever.com/myjs.js?rnd='+randnumber;

但是我只需要在JavaScript文件进行某些更新而不是在每次页面重新加载时清除缓存.

But I need to clear cache only when there is some update on the JavaScript files not on every reload of the page.

推荐答案

大多数站点(包括堆栈溢出)为此使用其版本控制系统中的修订号:

Most sites - including Stack Overflow - use a revision number from their version control system for this:

var scriptfile='http://www.whatever.com/myjs.js?rnd='+revision_number;

每当修订版本更改时，浏览器都会指向新的" JavaScript文件.

whenever the revision changes, the browser gets pointed to a "new" JavaScript file.

您也可以手动执行此操作，方法是在某个位置的中央位置指定版本号，然后将该版本号添加到每个脚本调用中.当您更新JavaScript的一部分时，只需增加版本号即可.

You can do this manually as well, by specifying a version number at a central place somewhere, and adding that version number to every script call. When you update a part of the JavaScript, you simply increment the version number.

第三种方法是检查所包含的JavaScript文件的上次修改"时间，并根据该时间构建时间戳:

A third approach would be checking the "last modified" time of the JavaScript files you are including, and building a timestamp from it:

var scriptfile='http://www.whatever.com/myjs.js?version=20100803';

但是这将需要服务器端脚本，并且可能对于每个页面请求而言都太昂贵了.

but that would require server-side scripting and may be too expensive to do on every page request.

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