Attribute syntax

• Empty (HTML only; <input disabled …)
• Unquoted (HTML only; <input value=yes …)
• Single quoted (<input type='checkbox' …)
• Double quoted (<input name="be evil" …)

Default attributes

• Omitted (<script>)
• Included (<script type="text/javascript">)

Optional tags (HTML only)

• Omitted (<p>foo<p>bar)
• Included (<p>foo</p><p>bar</p>)

Void elements (HTML only)

• No slash (<br>)
• With slash (<br/>)

Empty elements (XML only)

• Empty-element syntax (<div/>)
• Start tag, end tag (<div></div>)