Right, I think the person you’re replying to is partially correct in that the parser gets to “<br “ and recognizes that “this is be a br tag”, but it doesn’t close because tags can have any arbitrary attributes, and the W3C says br may also contain any of the global attributes. So, the parser indeed doesn’t just stop because it knows what tag it is and then doesn’t allow any attributes, it has to keep going until it reaches a valid closing “>”.