How to force IE to reload javascript?

Question

I'm using IE 8 on Vista, and everytime I change a javascript file and then start debugging, I have to hit Ctrl+F5 to have it reload my javascript. Is there any way to make it automatically reload javascript when I start debugging, but not lose the performance gains when just browsing the net?

Yeah yeah I know you probably don't like IE, but keep in mind the question isn't "What's the best browser?".

Answer 1

Add a string at the end of your URL to break the cache. I usually do (with PHP):

<script src="/my/js/file.js?<?=time()?>"></script>

So that it reloads every time while I'm working on it, and then take it off when it goes into production. In reality I abstract this out a little more but the idea remains the same.

If you check out the source of this website, they append the revision number at the end of the URL in a similar fashion to force the changes upon us whenever they update the javascript files.

Answer 2

When you work with web page or javascript file you want it to be reloaded every time you change it. You can change settings in IE 8 so the browser will never cache.

Follow this simple steps.

1. Select Tools-> Internet Options.
2. In General tab click on Settings button in Browsing history section.
3. Click on "Every time I visit the webpage" radio button.
4. Click OK button.

Answer 3

In javascript I think that it is not possible, because modern browsers have a policy on security in javascripts.. and clearing the cache is a very violating one.

You can try to add

<META HTTP-EQUIV="Pragma" CONTENT="no-cache">

In your header, but you will have performance loss.

Answer 4

Paolo's general idea (i.e. effectively changing some part of the request uri) is your best bet. However, I'd suggest using a more static value such as a version number that you update when you have changed your script file so that you can still get the performance gains of caching.

So either something like this:

<script src="/my/js/file.js?version=2.1.3" ></script>

or maybe

<script src="/my/js/file.2.1.3.js" ></script>

I prefer the first option because it means you can maintain the one file instead of having to constantly rename it (which for example maintains consistent version history in your source control). Of course either one (as I've described them) would involve updating your include statements each time, so you may want to come up with a dynamic way of doing it, such as replacing a fixed value with a dynamic one every time you deploy (using Ant or whatever).

Answer 5

"PRAGMA" tag seems to be working great! Thanks so much!