Animating in other Units

The YUI Animation Utility allows you to animate style attributes in any CSS unit.

The first thing we need to do is load the Animation source file and dependencies:

For this example, we will animate the width of the <div> element named demo in EM units. Using EMs is nice, because it becomes relative to the text size, and will scale as the user changes the browser text size setting.

Add a little style so that we can see the animation in action:

Create the demo element and a button to run the animation:

Now we create an instance of YAHOO.util.Anim, passing it the element we wish to animate, and the style attribute(s) to be animated. Because we are changing the unit to something other than the default ("px"), the from field is required:

The final step is to call the animate method on our instance to start the animation. To keep things simple, we will animate when the document is clicked:

This is an example of animating in units other than pixels.