Despite the huge bandwidth increases, websites don’t get much faster. This is because the biggest botteneck in loading web pages is latency.1
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 request, 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 mobiles.
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:
If your browser doesn’t support pushState3, InstantClick fully degrades.
Head to the Getting started page.
By decreasing order of priority:
You can follow InstantClick’s news on Twitter, or participate in InstantClick’s development on Github.