Comparative Analysis of the Performance of CSS Animation Methods (Transition and Animation) under High DOM Load

Abstract

This article presents a comparative performance analysis of two primary Cascading Style Sheets (CSS) animation methods — transition and animation — under conditions involving large-scale DOM rendering. Despite widespread beliefs among developers that transitions generally offer better performance, there is a lack of quantitative research validating this assumption in practical scenarios. To address this gap, we developed a web application capable of rendering and animating from 50 up to 10,000 elements simultaneously. Performance metrics were collected in real-time using built-in browser APIs, including average and minimum FPS, frame delta (time between frames), JavaScript heap memory usage, and total animation duration. Tests were conducted on the latest versions of Chrome and Firefox browsers. Results demonstrate that the choice of animation method heavily influences performance, the specific CSS property being animated (e.g., opacity, transform, blur, background-color), and the number of animated elements. While transitions showed slightly better efficiency in terms of JavaScript resource consumption, other metrics such as frame rate and rendering stability were comparable between the two methods. Notably, animations consistently require more memory, which may affect scalability in high-load interfaces. This research provides valuable quantitative data to guide front-end developers in selecting appropriate animation techniques for complex interfaces. It also emphasizes the importance of selecting GPU-friendly CSS properties to enhance rendering performance. Overall, the findings suggest that while the difference in performance between transitions and animations is modest, understanding their behavior under load is crucial for building smooth and responsive web experiences.