Modern JavaScript from the Beginning - Second Edition - requestAnimationFrame() Method

The video tutorial introduces the requestAnimationFrame method in JavaScript, explaining its role in creating smooth animations by synchronizing with the browser's repaint cycle. The instructor demonstrates setting up a basic animation, using timestamps to track elapsed time, and applying CSS transforms to animate elements. Advanced techniques like rotation are also covered, providing a comprehensive guide to creating animations in web development.

What is the primary purpose of the requestAnimationFrame method?

• To log messages to the console.

• To stop all animations on the page.

• To create a new window object for animations.

• To request the browser to perform an animation and update it before the next repaint.

In the basic animation loop, what is the role of the step function?

• To create a new image element.

• To log messages to the console and be called before each repaint.

• To stop the animation after a certain time.

• To change the background color of the page.

How can you calculate the elapsed time in a requestAnimationFrame loop?

• By using the current timestamp minus the start time.

• By using a fixed time interval.

• By counting the number of console logs.

• By measuring the screen refresh rate.

What condition is used to stop the animation after a certain duration?

• If the elapsed time is greater than a specified value.

• If the browser window is resized.

• If the console log count reaches a certain number.

• If the elapsed time is less than a specified value.

Which CSS property is used to move an element horizontally across the page?

• scale

• translateX

• translateY

• rotate

What unit is used for the rotation transformation in CSS?

• Degrees (deg)

• Pixels (px)

• Seconds (s)

• Percentage (%)

How can you make an element rotate while it moves across the page?

• By using the scale property.

• By using a fixed position.

• By applying both translateX and rotate transformations.

• By changing the background color.