What are the actual problems of not closing tags and attributes in HTML

Question

Recently a friend decided not to close his tags or attributes in HTML because it\'s not required and he\'ll save some bandwidth and download time. I told him it\'s a bad ide

Answer 1

Not closing tags can lead to browser incompatibilities and improperly rendered pages. That alone should be enough reason to properly close your tags.

Saving bandwidth and download time is a horrible excuse, if you ask me. It's 2011, and even on dialup the few bytes you save on not closing a few tags will not be even close to noticeable. A mangled page due to improper rendering, however, will be.