InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.

Why

Despite huge bandwidth increases, websites don’t get much faster. This is because the biggest bottleneck in loading web pages is latency.1

How does it work

Latency is inevitable with today’s internet architecture so InstantClick cheats by preloading links you are likely to click on.

Before visitors click on a link, they hover over that link. Between these two events, 200 ms to 300 ms usually pass by (test yourself here). InstantClick makes use of that time to preload the page, so that the page is already there when you click.

On mobile devices, preloading starts on “touchstart”, letting 300 ms (Android) to 450 ms (iOS) for preloading the page.2

If you want your website to not be flooded by requests, you can set a delay before preloading starts when users hover a link. It will still feel instant.

If you don’t want any wasted requests, you may preload on “mousedown”. This is when you press your mouse button (a click is when you release it).

When loading pages with InstantClick, the browser doesn’t show its standard loading indicators anymore. To make sure the user knows a page has changed, InstantClick includes a (customizable) progress bar.3 The bar automatically scales to appropriate size on mobile devices, so it works even when your site isn’t optimized for mobile.


InstantClick uses pushState and Ajax (a combo known as pjax), replacing only the body and the title in the head.

Ajax brings two nice benefits in and of itself:

InstantClick supports the following browsers’ versions:

IE Firefox Chrome Safari Opera iOS Safari Android Browser Chrome for Android
10+ 4.0+ 5+ 5.0+ 11.5+ 5.0+ 4.4+ 18+

According to StatCounter, over 80% of the world supports InstantClick. When a browser doesn't support it, InstantClick fully degrades.

Getting started

Head to the Download page and follow the instructions.

You can follow InstantClick’s news on Twitter, or participate in InstantClick’s development on Github.

Footnotes

  1. Check out Latency: The New Web Performance Bottleneck for a good summary about bandwidth vs. latency effects on web pages. 
  2. On 3G, requests usually take 200 ms. 
  3. The progress bar is fake, much like NProgress. Though it seems possible that a future version of InstantClick could show real progress by checking the HTTP Content-Length header.