CSS rotation cross browser with jquery.animate()

CSS-Transforms are not possible to animate with jQuery, yet. You can do something like this:

function AnimateRotate(angle) {
    // caching the object for performance reasons
    var $elem = $('#MyDiv2');

    // we use a pseudo object for the animation
    // (starts from `0` to `angle`), you can name it as you want
    $({deg: 0}).animate({deg: angle}, {
        duration: 2000,
        step: function(now) {
            // in the step-callback (that is fired each step of the animation),
            // you can use the `now` paramter which contains the current
            // animation-position (`0` up to `angle`)
            $elem.css({
                transform: 'rotate(' + now + 'deg)'
            });
        }
    });
}

You can read more about the step-callback here: http://api.jquery.com/animate/#step

http://jsfiddle.net/UB2XR/23/

And, btw: you don't need to prefix css3 transforms with jQuery 1.7+

Update

You can wrap this in a jQuery-plugin to make your life a bit easier:

$.fn.animateRotate = function(angle, duration, easing, complete) {
  return this.each(function() {
    var $elem = $(this);

    $({deg: 0}).animate({deg: angle}, {
      duration: duration,
      easing: easing,
      step: function(now) {
        $elem.css({
           transform: 'rotate(' + now + 'deg)'
         });
      },
      complete: complete || $.noop
    });
  });
};

$('#MyDiv2').animateRotate(90);

http://jsbin.com/ofagog/2/edit

Update2

I optimized it a bit to make the order of easing, duration and complete insignificant.

$.fn.animateRotate = function(angle, duration, easing, complete) {
  var args = $.speed(duration, easing, complete);
  var step = args.step;
  return this.each(function(i, e) {
    args.complete = $.proxy(args.complete, e);
    args.step = function(now) {
      $.style(e, 'transform', 'rotate(' + now + 'deg)');
      if (step) return step.apply(e, arguments);
    };

    $({deg: 0}).animate({deg: angle}, args);
  });
};

Update 2.1

Thanks to matteo who noted an issue with the this-context in the complete-callback. If fixed it by binding the callback with jQuery.proxy on each node.

I've added the edition to the code before from Update 2.

Update 2.2

This is a possible modification if you want to do something like toggle the rotation back and forth. I simply added a start parameter to the function and replaced this line:

$({deg: start}).animate({deg: angle}, args);

If anyone knows how to make this more generic for all use cases, whether or not they want to set a start degree, please make the appropriate edit.

---

The Usage^{...is quite simple!}

Mainly you've two ways to reach the desired result. But at the first, let's take a look on the arguments:

jQuery.fn.animateRotate(angle, duration, easing, complete)

Except of "angle" are all of them optional and fallback to the default jQuery.fn.animate-properties:

duration: 400
easing: "swing"
complete: function () {}

1st

This way is the short one, but looks a bit unclear the more arguments we pass in.

$(node).animateRotate(90);
$(node).animateRotate(90, function () {});
$(node).animateRotate(90, 1337, 'linear', function () {});

2nd

I prefer to use objects if there are more than three arguments, so this syntax is my favorit:

$(node).animateRotate(90, {
  duration: 1337,
  easing: 'linear',
  complete: function () {},
  step: function () {}
});