"Well, for those of you who are really addicted to X(HT)ML, you might think, «yeah, it's optional, but <br /> is still 'more correct'», but I have to tell you: it is not. Actually, one might argue that adding / to a void tag is an ignored syntax error. The possibility to write it has mostly been added for compatibility reasons and every browser and parser should not handle <br> and <br /> any differently.

Google's styleguide on that subject is also very clear that you should indeed not close void tags."