What is the purpose of the will-change property in CSS?

• A. It forces hardware acceleration for the element
• B. It changes the stacking context during animations
• C. It hints the browser about upcoming changes to optimize painting
• D. It sets a default transition for the element

Answer: (C)

Will-change is a hint to the browser that an element will undergo certain changes soon, usually during animations. By signaling which properties will change (like transform or opacity), the browser can prepare in advance, often by creating a separate compositing layer and optimizing how painting and compositing will happen. This can make animations appear smoother because the engine handles those changes more efficiently.

It doesn’t force hardware acceleration, nor does it change stacking context or set a default transition. Use it only for elements that will actually animate and remove it after the animation ends to avoid unnecessary memory use.