How can I prevent javascript caching? Querystring approach isn't working

Question

I've seen other approaches that attach a version number or MD5 hash to a JS src querystring.

e.g. <script src='/script/v1/'></script>

However, my JavaScript is still getting cached in multiple browsers (Chrome, Firefox) when I push a new version of my site.

This seems like a major problem that others have solved, and I seem to be doing the right things. How can I get this to work?

Then I fear the files are cached in the server memory.. here is something that led me in this direction: redmine.lighttpd.net/wiki/1/Docs:ModMemCache — user447356
– user447356, Commented Apr 4, 2011 at 21:24
Anyone knows if query string appending is reliable? i.e. /script.js?v=1.1 I usually use here /script_timestamp.js but would prefer the querystring approach (looks cleaner to me). — turtlepick
– turtlepick, Commented Jun 27, 2012 at 23:14
@flaviotsf - look at my answer below, specifically the reference to Steve Souders' blog. — marclar
– marclar, Commented Jun 28, 2012 at 14:23

marclar · Accepted Answer · 2011-05-05 13:52:44Z

7

I added log messages and determined that the querystring method is working. Sorry for the unnecessary question.

However, in researching, I found some important points worth mentioning:

One of the articles suggests using a querystring with the current time appended. You probably don't want to follow this suggestion as your files will never be cached. Using source control version numbers or an MD5 hash would be better.
Steve Souders (of High Performance Web Sites fame) notes that certain web proxies never cache anything with a querystring. Thus, the version number should be embedded within the path to the file in order to ensure that your files are cached appropriately when accessed through these proxies. ( http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/ )

edited May 5, 2011 at 13:52

answered May 5, 2011 at 13:42

marclar

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Comments

tiagoboldt · Accepted Answer · 2011-04-04 16:24:02Z

1

It will be cached always. Although, by using a version number (or any other varying string) a new version will be downloaded and used every time, ignoring the previous one.

http://thecrmgrid.wordpress.com/2007/10/22/prevent-caching-of-javascript-include-files-during-development/

http://davidwalsh.name/prevent-cache

answered Apr 4, 2011 at 16:24

tiagoboldt

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2 Comments

marclar Over a year ago

That's what I'm saying -- I do that and it's not working. Everyone in my company experiences this frequently, and I swear we're not dumbasses. Hence my question and confusion.

tiagoboldt Over a year ago

That's the expected behavior. Still, by appending ?something to the file name, you will force a new version to be downloaded (and cached), avoid the browsers cache.

Dave L. · Accepted Answer · 2011-04-04 16:25:22Z

0

1.)make sure the response headers for the javascript files are correct and include expires, cache-control, etc.

2.)you probably have to append the version not as a query parameter but part of the filename, e.g. page_v.2.js. You could change the javascript filenames at build time for example if you are using Java. That is what i have done.

answered Apr 4, 2011 at 16:25

Dave L.

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2 Comments

marclar Over a year ago

Edited my question to show that that's actually what we do -- it's not a querystring parameter, it's a unique URL based on the MD5 hash.

marclar Over a year ago

Will check the expires & cache-control settings.

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