ken ken - 6 months ago 19
Javascript Question

jQuery .get caching working too well?

I'm using the jQuery .get() function to load in a template file and then display the loaded HTML into a part of the page by targeting a particular DOM element. It works well but I've recently realised for reasons that confound me that it is caching my template files and masking changes I have made.

Don't get me wrong ... I like caching as much as the next guy. I want it to cache when there's no timestamp difference between the client's cache and the file on the server. However, that's not what is happening. To make it even odder ... using the same function to load the templates ... some template files are loading the updates and others are not (preferring the cached version over recent changes).

Below is the loading function I use.

function LoadTemplateFile ( DOMlocation , templateFile , addEventsFlag ) {
$.get( templateFile , function (data) {
$( DOMlocation ).html(data);
});
}


Any help would be greatly appreciated.

NEW DETAILS:
I've been doing some debugging and now see that the "data" variable that comes back to the success function does have the newer information but for reasons that are not yet clear to me what's inserted into the DOM is an old version. How in heck this would happen has now become my question.

Answer

You can set caching to off in the jQuery.get() call. See the jQuery.ajax() doc for details with the cache: false option. The details of how caching works is browser specific so I don't think you can control how it works, just whether it's on or off for any given call.

FYI, when you turn caching off, jQuery bypasses the browser caching by appending a unique timestamp parameter to the end of the URL which makes it not match any previous URL, thus there is no cache hit.

You can probably also control cache lifetime and several other caching parameters on your server which will set various HTTP headers that instruct the browser what types of caching to allow. When developing your app, you probably want caching off entirely. For deployment, I would suggest that you want it on and then when you rev your app, the safest way to deal with caching is to change your URLs slightly so the new versions of your URLs are different. That way, you always get max caching, but also users get new versions immediately.