What file format is commonly used for animation on the internet?

The most commonly used file format for animation on the internet is SWF (Shockwave Flash). This format was developed by Adobe (originally Macromedia) for the purpose of creating animations and interactive content that can be easily embedded in web pages. SWF files support vector graphics, allowing for scalable animations that maintain quality at various sizes, making them ideal for web use. They also support sound, which adds an engaging element to animations.

While other formats like GIF are known for supporting simple animations, they come with limitations, particularly in terms of color depth and resolution. MP4 is primarily a video format that is great for high-quality video playback but not as well suited for simple animations. AVI is less common on the web due to its larger file size and less efficient compression, making it less suitable for online content.

The ability of SWF to deliver rich multimedia experiences on the web has made it a popular choice for web-based animations, despite the growing trend towards HTML5 and its capabilities in more recent years.