Why you should REALLY use the HTML5 manifest option

Think of it as “browser cache under your control”. If you really dive into the HTML5 functionality, there are so many things to improve on websites now. Let me ride only the manifest here for a few sentences to bring that concept into your daily routine as a web site developer!

A few easy things about the manifest:

First: Your web server must know the mime type – that is a single line you might either add to your .htaccess file or your basic apache configuration:

AddType text/cache-manifest .manifest

The file suffix might be anything you like. We have decided to use .appcache here on orga.zone.

Second: It is REALLY simple to add. Just expand the HTML opening tag of your page like this

<html manifest="orga.appcache">

Third: Remember that the manifest nails the content you determine into the browser and that is only updated, if you change the manifest. That causes some confusion for developers, but once you get the idea behind it, you will love the speed of your site and your users will, too!

Why is that important?

The major reason to use the manifest is speed, especially when you work with CDN hosted Javascript libraries like jquery or bootstrap. Whenever the user returns to your site and you have “manifested the libraries into the browser cache”, the page load speed goes up significantly. Yes, normal caching works the same way and your sub pages are fast in a session anyhow – think “returning surfers” and those who have ended their mobile browser yesterday and show up today again to continue on your site.


For example: if you use 3 or 4 libraries with Javascript and you put these libs into the manifest, the browser will not even look into the web to pick those up when your site is loaded again – only if you update your manifest.

That technology is intended to make mobile pages really fast, especially for your news sites and reader heavy pages: bring your logo, standard libraries and other bigger files that RARELY change into that manifest, so these will still be there, if the user kills the browser and comes back next week – or even more interesting for those of you, who want think “mobile first”: if the user is on a thin Edge connection the next time, everything is faster!

If you need more details: this article is now 4 years old and becomes more true every day!


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