.js file being downloaded twice once from cache

 · A client wanted to know how to 'force' a client to update some javascript that the browser had cached. The easy answer is "change the file." Here's what happens with a single HTML file and a single JavaScript file, running locally on my machine. The main directory is set to "Expire Immediately" via IIS's properties dialog.  · Even if the CSS file took longer than the JavaScript file to download, the CSS would be evaluated first due to CSS being render blocking. This is a good thing as it prevents the dreaded FOUC. We have achieved our goal of being able to manage the caching (and cache busting) of the application files. we can now call window.  · Sometimes, JavaScript modification doesn’t reflect on the page while running the need to clear browser cache manually each time when the file gets updated. It makes the debugging process hard. If the project contains some bug and you fix it but the user needs to clear the browser cache to reflect the changes.

This would include aspx, asmx, ashx, and svc type of requests. However in this scenario I would see large JavaScript files being loaded each time I open the form. I have a couple screenshots below showing the common offenders. These static files can account for nearly 1MB of extra data being downloaded with each form load. Avoiding bugs from cached JavaScript and CSS files in SharePoint. This article got quite detailed so here's an executive summary - if you store custom JavaScript/CSS files etc. somewhere under SharePoint's 'layouts' folder (or upload them manually to a library within the site), make sure the URL changes on each update. bltadwin.ru is half the size of the other two streaming players. Once the JS is downloaded, it must be parsed before the first video request can be made. In WebPageTest, this is seen as a delay between requests (the pink lines show CPU processing). Using a Motorola G4, we see a gap in content download from s to s as the JavaScript is being parsed.

Show activity on this post. When you do an IISReset the IIS cache will be cleared and then will start to be rebuilt after it starts back up as client requests come in. If you update a file then the older cached file will become stale and IIS will serve the updated file and update the cache with the new file. IISReset (although harsh) will clear. I did not mean to say, that the files are being added to the appcache twice. they are being downloaded twice. So the first lot ends up in the normal browser cache the second in the appcache with the hashed file name as well. that is the reason why the are downloaded twice. A client wanted to know how to 'force' a client to update some javascript that the browser had cached. The easy answer is "change the file." Here's what happens with a single HTML file and a single JavaScript file, running locally on my machine. The main directory is set to "Expire Immediately" via IIS's properties dialog.