I am confused. A co-worker turned me on to the possibility that tags ending in />, such as <br /> can still be used in HTML5. I thought that only <br>-style could be used. All of the "talk" across the Internet is about using the latter.
Could someone please explain this to me? This seems very confusing and poorly documented.
And this brings up another question: Is HTML 5 considered to be well-formed XML?
question from:https://stackoverflow.com/questions/5558502/is-html5-valid-xml
No. Counter-examples:
These are valid HTML5 but invalid XHTML5:
Some closing tags can be omitted:
<p>First
<p>Second
script escape magic:
<script><a></script>
Attributes without values (boolean attributes):
<input type="text" disabled />
Attributes without quotes, e.g.:
<div data-a=b></div>
See: In XHTML 1.0 Strict do attribute values need to be surrounded with quotes?
Implicit open elements and multiple top level elements.
Some HTML elements are created implicitly. E.g. html. This allows the HTML to have "multiple top level elements":
<!doctype html><title>a</title><p>a</p>
Valid XHTML that is invalid HTML:
CDATA constructs with invalid tags inside
ENTITY and other exclamation mark constructs, which allow for billion laughs: How does the billion laughs XML DoS attack work?
Valid HTML and XHTML but with different meanings:
£, ©), XML has only 5 (quot, amp, apos, lt, gt).