The integration of CSS animations with JavaScript offers greater control and flexibility to manipulate animations in response to events and dynamic conditions. JavaScript can start, stop, and modify the animation on the fly, allowing for more advanced interactivity.

Manipulate Animations with JavaScript

JavaScript can interact with CSS properties to manipulate animations. Below are some of the most common actions you can perform:

1. Start and Stop Animations

Using JavaScript, you can add or remove CSS classes that control animations.

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In this example, startAnimation adds the class animate to the div box, starting the animation. stopAnimation removes the class animate, stopping the animation.

2. Dynamically Change Animation Properties

JavaScript can directly modify CSS properties using style or by manipulating classes.

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In this example, changeDuration modifies the animation duration by changing the animationDuration property of the div element.

3. Using Animation Events

JavaScript can detect and react to various animation events: animationstart, animationiteration, and animationend.

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In this example, animation events are registered and messages are printed to the console when animations start, repeat, or end.

Using the Web Animations API

The Web Animations API provides more advanced and precise methods to control animations.

1. Create and Control Animations

You can define and control animations directly in JavaScript using the Web Animations API.

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In this example, the animation is defined and controlled using the Web Animations API. startAnimation plays the animation, while pauseAnimation pauses it.

[Placeholder for image: Visual example showing a button starting and another pausing an animation applied to a box, with JavaScript controlling the process]

Best Practices

1. Keep it Compatible: Ensure that JavaScript-controlled animations are compatible with all browsers used by your users.
2. Use CSS Classes: Whenever possible, use CSS classes to manipulate animations instead of directly modifying individual properties.
3. Event Handling: Leverage animation events to take actions at key moments in the animation cycle.

Integrating CSS animations with JavaScript allows for richer and more dynamic interactivity in web experiences. In the next section, we will cover tools and libraries you can use to simplify and enhance your CSS animations.