Why add?v=._html/css_WEB-ITnose after css or js

Why add ?v=...
What technology is this?

http://www.plu.cn/static/sc/layout/sc-build.css?v=1.1
http://.../jquery.js?v=1.3. 2

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In order to pass parameters~·

Sometimes pages need to pass parameters to each other, jump The value that should be used to jump to the next page

In order to pass parameters~·

Sometimes pages need to pass parameters to each other. Is this the value that should be used to jump to the next page? How to receive this parameter in css or js?

Because JS or CSS may be modified, in order to notify the user that the file has been modified, do not read the local cache, but go to the server to re-download it

Most of the time, this is to update the version. Or when there are occasional changes, users can see them in time. Otherwise, since there will be a cache in the user's machine and their addresses are the same, the changed files will not be re-downloaded, and the changed content will not be visible.

For CSS, it cannot receive any parameters. Only JS can also have this function. This is when necessary. You will know it when you encounter it. If you don’t encounter it, you don’t need to worry about it.

Avoid outdated cache

Just avoid updating, but when the browser accesses it, the updated files are not obtained in time.

Why add ?v=...
What technology is this?

http://www.plu.cn/static/sc/layout/sc-build.css?v=1.1
http://.../jquery.js?v=1.3. 2
Looking at this format, the value after v should be the version number.
Generally, if there are major changes to files such as css and js, adding a version number can replace the js and css in the client cache. On the other hand, this will also help with the management of js and css

It says like this http://.../jquery.js It’s okay not to add it, but if it is updated in the future, if the name is still jquery .js, the browser may not reload because the names are the same and the cache is read directly. If you make v=123 or d456, the name will change. When the browser sees that the name has changed, it will download the js file again. I usually write /jquery.js?diyici like this. When it is updated in the future, I will change it to dierci, disanci, and so on, so as not to make it the same name and the browser will think that you have not updated it. If it is /jquery.js?diyici for the first time, and it is still written as /jquery.js?diyici after updating the JS file, it is the same as /jquery.js, which is meaningless.