Which browser version first supported GIF repeat animations?

Netscape Navigator 2.0 was the first browser version to support GIF repeat animations.

Netscape added looping support in September 1995. The browser recognized the Netscape Application Block, an application extension placed in a GIF file to specify how many times its frames should repeat. With a repeat count of zero, an animation could continue indefinitely instead of stopping after one pass.

This feature built on capabilities already present in GIF89a, the 1989 revision of the format. GIF89a added animation-related features such as frame delays, but the repeat instruction was a later, proprietary convention. Other browsers eventually implemented the same convention, helping animated GIFs become a standard part of early Web design.

The answer is sometimes confused with general animated-GIF support. Navigator 2.0 is specifically associated with repeat animations, not merely displaying a still GIF or a multi-frame file. The release also introduced or expanded several landmark Web features, including JavaScript support, plug-ins, progressive JPEG support, and HTML frames.