Question

I have a web app written in ASP.NET MVC 3.0. There are some largish scripts (jQuery, jQuery UI) which I want to ensure are cached for best performance. In the Chrome Developer Tools Network tab the scripts always take around 1.5 seconds to be received when a page is loaded. I would assume if they are cached this would be near instant.

Is there any way to ensure javascript is being cached and how to tell if it is or isn’t?

Answer 1

For JQuery in particular it is better to use someone elses CDN – you will not have to stream this content from your server AND caching is properly done by someone else. See http://docs.jquery.com/Downloading_jQuery for recommended CDNs.

For files that you have to host yourself make sure you set correct caching headers.

• For static content you need to rely on server (likley IIS in ASP.Net case) to set correct headers – see http://support.microsoft.com/kb/247404 for some detais, search for “iis cache control” to get more links.
• For dynamic content choose needed values OutputCache attributes or set headers yourself (i.e. see http://www.asp.net/mvc/tutorials/improving-performance-with-output-caching-cs ).