网页中使用的外部JS文件的控制到期

Question

In order to cause the javascript file to expire on a web page perhaps someone could answer any of the following specific questions:

1. Does the script file expire when the page expires?
2. Should I add a version number to the name of my various script files (and html pages?)
3. If there is no attribute for expiry, is there server side header info that can be added to the script?
4. Is there a recommended best practice(s) where this is concerned?

Answer 1

1) Does the script file expire when the page expires?

No, it expires according to the caching information provided when the js file was served up, unless it is an html application in which case it can be expired earlier by changing the timestamp on the manifest file.

2) Should I add a version number to the name of my various script files (and html pages?)

This is a common practice for static content in combination with a very long expiry time

3) If there is no attribute for expiry, is there server side header info that can be added to the script?

No (you can embed meta header data in HTML but not in other content types).

4) Is there a recommended best practice(s) where this is concerned?

Yes, there's lots of "best practices". Usually option 2 with the added caveat that the version information should be in the path rather than the query. Doing this by hand can be a PITA: mod_pagespeed (and some other tools) do it automagically.