Animated cursor support in web applications?

You can make it happen with the help of a bit of javascript:

Add to your css

#container {
   cursor   : none;
}

#cursor {
  position  : absolute;
  z-index   : 10000;
  width     : 40px;
  height    : 40px;
  background: transparent url(../images/cursor.gif) 0 0 no-repeat;
}

Then add to your js

Straight Javascript Version

// Set the offset so the the mouse pointer matches your gif's pointer
var cursorOffset = {
   left : -30
 , top  : -20
}

document.getElementById('container').addEventListener("mousemove", function (e) {
  var $cursor = document.getElementById('cursor')

  $cursor.style.left = (e.pageX - cursorOffset.left) + 'px';
  $cursor.style.top = (e.pageY - cursorOffset.top) + 'px';

}, false);

Jquery Version

$('#container').on("mousemove", function (e) {
  $('#cursor').offset({ 
     left: (e.pageX - cursorOffset.left)
   , top : (e.pageY - cursorOffset.top)
  })

});

To answer your question

Do any web browsers support animated cursors?

Yes.According to MDN, IE supports .cur and .ani formats.

As a suggestion,have you considered using an animated gif image instead?

Try this in your css

cursor: url(img/animated_cursor.gif), auto;

I managed to accomplish this using CSS keyframes, animating the source image of the cursor. It works in Chrome and Safari (though it can get a little glitchy if you've got a ton of stuff running). Good enough for my personal site!

* {
  cursor: url(frame1.png), auto;
  -webkit-animation: cursor 400ms infinite;
  animation: cursor 400ms infinite;
}

@-webkit-keyframes cursor {
  0% {cursor: url(frame1.png), auto;}
  20% {cursor: url(frame2.png), auto;}
  40% {cursor: url(frame3.png), auto;}
  60% {cursor: url(frame4.png), auto;}
  80% {cursor: url(frame5.png), auto;}
  100% {cursor: url(frame6.png), auto;}
} 

@keyframes cursor {
  0% {cursor: url(frame1.png), auto;}
  20% {cursor: url(frame2.png), auto;}
  40% {cursor: url(frame3.png), auto;}
  60% {cursor: url(frame4.png), auto;}
  80% {cursor: url(frame5.png), auto;}
  100% {cursor: url(frame6.png), auto;}
}

After doing some more research, I don't think it's possible at the moment. It doesn't seem that any of the browsers support animated cursors as of 2/8/2012 using the CSS cursor property. I suppose it could be done using JavaScript to repeatedly change the value of the cursor property every few frames to make it appear animated, but that may be more trouble than it is worth.

Animated cursor files .ani files do not work. All 5 major web browsers will not show the cursor. If you try some CSS like, cursor: url('animated.ani'), that cursor will not show up!

If you make the cursor an animated gif file, it only shows up on some browsers and it's temperamental, like cursor: url('animated.gif'), the cursor works in Firefox and Chrome but it is not animated, the cursor does not work at all in IE9 or Opera, and it did something really weird in the Windows version of Safari - it works but is only animated when I move the cursor vertically on the screen, and did not animate at all when the cursor was not moving or was moving horizontally. Credit to Brutallus for the idea to use an animated gif even though it did not work!

It doesn't seem that browsers support animated cursors at this time which is a shame because I really think it would add some depth to certain web applications. I don't advocate using animated cursors for most websites because they are extremely annoying, but there are some rare situations where they can be useful, such as a HTML5 game where the cursor can potentially add to the theme of the game.