FastClick

FastClick is a JavaScript library developed by FT Labs that removes the 300-millisecond delay on click events in mobile browsers. This delay was originally introduced by mobile browsers to distinguish between a single tap and a double-tap. FastClick achieves this by listening for touch events and programmatically triggering a "click" event on the element that was touched. This results in a faster, more responsive user experience on touch devices, as the click event fires almost instantaneously.

The library is lightweight and easy to implement. It can be initialized by simply calling FastClick.attach() with the element that needs to have the delay removed, or by attaching it to the entire document. FastClick is designed to work with most modern mobile browsers, including those on iOS, Android, and Windows Phone. It is also compatible with various web frameworks and libraries.

While FastClick significantly improves click responsiveness, it's important to note that it is a shim. Modern mobile browsers have increasingly adopted standards that reduce or eliminate this 300ms delay natively. Therefore, in many newer browser versions, FastClick may no longer be strictly necessary. However, it remains a useful tool for ensuring consistent performance across a wider range of devices and browser versions, especially for older or less updated mobile operating systems. Its primary benefit is the immediate feedback users receive when interacting with buttons and links on mobile websites.