Learning jQuery 3 - Fifth Edition

Taking fine-grained control of animations

Even though we've looked at a number of advanced features, jQuery's effects module has much more to explore. A rewrite of this module for jQuery 1.8 introduced a number of ways for advanced developers to fine-tune various effects and even change the underlying engine that drives the animations. For example, in addition to offering options such as duration and easing, the .animate() method provides a couple of callback options that let us inspect and modify an animation each step of the way:

$('#mydiv').animate({   height: '200px',   width: '400px' }, {   step(now, tween) {    // monitor height and width    // adjust tween properties   },   progress(animation, progress, remainingMs) {} }); 

The step() function, ...