From the W3C specification for HTML:
The following is a complete list of the void elements in HTML:
area, base, br, col, command, embed, hr, img, input, keygen, link, meta, param, source, track, wbr
Void elements only have a start tag; end tags must not be specified for void elements.
Start tags consist of the following parts, in exactly the following order:
- A
< character.
- The element’s tag name.
- Optionally, one or more attributes, each of which must be preceded by one or more space characters.
- Optionally, one or more space characters.
- Optionally, a
/ character, which may be present only if the element is a void element.
- A
> character.
From this it seems that we can use either <br> or <br/>. However, the end tag </br> is not valid, so don't use <br> </br>.
Running the following through the HTML Validation Service indicates as much.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Testing void elements</title>
</head>
<body>
some lines of txt <br>
and then some more <br />
I'm not done yet... <br> </br> <!-- This line generates an error -->
</body>
</html>
So use either <br> or <br/>, just make sure you use them consistently.
Edit: As noted by Brad, <br /> is also valid XHTML, so perhaps it is best to choose this form.
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