Unity WebGL supports all major desktop browsers to some degree. However, the level of support and the expected performance varies between different browsers. See the table below for an overview of browser features of interest to Unity WebGL content, and which browsers support them.
Note that Unity WebGL content is not currently supported on mobile devices. Continue. It may still work, especially on high-end devices, but many current devices are not powerful enough and don’t have enough memory to support Unity WebGL content well. For this reason, Unity WebGL shows a warning message when trying to load content on mobile browsers (which can be disabled if needed).
Note that this compatibility table is valid for the specific versions of the browsers as stated. Support should continue for future versions, but may not be stable in previous versions.