Auto-Versioning inline Javascript in a PHP File?

Question

I have the following question / problem: I know that if I append something like "?v=*" in my Javascript includes such as <script src="/js/myJsFile1.js?v=1.1" type="text/javascript"></script> I can force a client side recaching.

Now my question is, if I have a fragment such as the following in an example.php...

<?php ... ?> 
<script> 
    var a = 5; 
    callRandomFunction(); 
</script>

...is there a need to have a version-control for this fragment as well? As it is included in a PHP File and therefore always called from the server anyway, does a forced caching make sense here?
If it does - Is there some similar way as there is with the "?v=" appendix?

If you are directly accessing "example.php", then no; it will be reloaded when you open that file. With that said, caching is a good thing. I would not recommend preventing caching of JS files outside of a development build unless you have a good reason. — Liftoff
– Liftoff, Commented Oct 20, 2021 at 8:06

IMSoP · Accepted Answer · 2021-10-20 12:51:04Z

3

A few points of confusion:

"caching" refers to re-using content; the techniques you are talking about are not "forced caching", they are forcing the browser not to use a cached copy
the parameter doesn't mean anything to the browser, it just means that this is a URL the browser has never seen before, so it won't have a cached copy
the browser doesn't see that something is part of a PHP page, only that it's part of an HTML page
the browser doesn't cache parts of pages, so if that HTML page is cached, the JS inside the page is cached too; if it is not, it is not
- to be clear, JS served on a separate URL but referenced in the HTML page will be cached separately, which is why changing the URL for each version makes a difference

So, the question comes down to:

Will my HTML page be cached?

The answer depends on cache headers, which are a surprisingly complicated part of HTTP. But the short version is that PHP will generally set headers telling the browser not to cache pages it generates.

So the really short answer is: no, you don't need to do anything.

edited Oct 20, 2021 at 12:51

answered Oct 20, 2021 at 8:07

IMSoP

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2 Comments

ccov77 Over a year ago

good points here. I’d just add that it is possible to have a cached Html page without caching one or more of its dependencies. For instance the JS can be served with an always refresh policy, even if the html has been served from the cache

IMSoP Over a year ago

@Juan Yes, good point, I've added a bullet to clarify that JS in the page is not the same as JS referenced from the page

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