CODEWITHSUNDEEP
httpbrowser-cache
burnt1ce
burnt1ce

Reputation: 14897

Does reducing the number of http requests matter if they are cached?

I have about 10 referenced CSS and JavaScript (JS) files on my website and I can combine them so there's only 2 CSS and JS files for the web browser client to download. Combining the files would decrease the number of HTTP requests and decrease page load times.

My question is: if those 10 CSS and JS files are cached after the first page load, would the 2nd page load time be just as fast as the page that has only 2 combined CSS and JS files? I would think so because cached files would no require an HTTP request. I understand that there are command scripts that can automate combining CSS and JS files for deployments but doing that would complicate future junior programmers/web designers that may work on website. The website is for a charity organization and there's very little control and available human resources to keep things in check and in order.

Update: My assumptions that using a cached file do not require an HTTP is wrong.

Upvotes: 3

Views: 524

Answers (3)

Arnold Zokas
Arnold Zokas

Reputation: 8580

Yes, you should reduce number of requests even if resources are cached. Two reasons:

1: There is a small performance hit (per file) even for cached files

If you profile your website, you will see that for every resource there is still a roundtrip being made to the server. If the resource has not been updated the server will return HTTP status code 304 - Not Modified, otherwise it will return HTTP status code 200 (and the resource itself).

Here's a sample trace produced by profiling Stack Overflow homepage CSS files:

enter image description here

As you can see, even though the CSS file is cached, a request was made to make sure the cached version is up to date.

2: First-time visitors will also benefit from this optimisation

It will improve page load speed for first-time visitors and anyone with a stale cache.

Upvotes: 4

Darcy
Darcy

Reputation: 5368

It's true that as soon as the files are loaded and cached, it doesn't matter how many files the css and js are split into, the speeds will be the same.

Of course, every time a user clears their cache the 10 files will be served again, thus causing more http requests.

In general, it's better to have as few files to server as possible, especially when your site is visited by a large number of users. Whenever you can save on http requests you should.

Upvotes: 0

Cyberon
Cyberon

Reputation: 289

Yes you should, browsers will get content size to determine whether the file has been changed or not. So no matter if browser already cached it ,it will always send http requests.

Upvotes: 1

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