InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.
25 December: version 3.1 is here, with support for dynamically added links!
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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:
- Your browser doesn’t have to throw and recompile scripts and styles on each page change anymore.
- You don’t get a white flash while your browser is waiting for a page to display, making your website feel faster.
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 Can I use, 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.