Development

Today Firefox announced support for preload will be added to today’s build of Firefox.

Using preload links to declaratively specify which resources the user agent must fetch early to improve page performance. 

According to https://caniuse.com/#search=preload preload is supported in Chrome, Opera and Android browser (Firefox has yet to be added)

Early fetch of critical resources example:

<link rel="preload" href="/assets/font.woff2" as="font" type="font/woff2">
<link rel="preload" href="/style/other.css" as="style">
<link rel="preload" href="//example.com/resource" as="fetch" crossorigin>
<link rel="preload" href="https://fonts.example.com/font.woff2" as="font" crossorigin type="font/woff2">