Like anything ever, there'll be a reliably-implemented common core, and a variety of corner-cases that are handled differently across implementations.
For example, Firefox fails some of those tests because if you call `canvas.getContext()` and pass a gibberish context-name, it throws an exception rather than returning `null`. Once there are any standardised context-names besides "`2d`", this might be a problem; I expect Mozilla will have fixed it by then.
For example, Firefox fails some of those tests because if you call `canvas.getContext()` and pass a gibberish context-name, it throws an exception rather than returning `null`. Once there are any standardised context-names besides "`2d`", this might be a problem; I expect Mozilla will have fixed it by then.