Should I use <br /> or <br>?

[felgall]

@Jeff_Mott

The reason many people think the space is required or that empty element closing tags are forbidden is because almost everyone this entire time has only ever been writing HTML-compatible XHTML.

The most recent browser for which the space is necessary in HTML-compatible XHTML is Netscape 4. All more recent browsers will accept it as HTML without the space.

So <br/> is acceptable for HTML compatible XHTML unless you still need to support Netscape 4.