Here's a simple block:
<div>
foo
</div>
This should be a code block, though:
<div>
foo
</div>
As should this:
<div>foo</div>
Now, nested:
<div>
<div>
<div>
foo
</div>
</div>
</div>
This should just be an HTML comment:
<!-- Comment -->
Multiline:
<!--
Blah
Blah
-->
Code block:
<!-- Comment -->
Just plain comment, with trailing spaces on the line:
<!-- foo -->
Code:
<hr />
Hr's:
<hr>
<hr/>
<hr />
<hr>
<hr/>
<hr />
<hr class="foo" id="bar" />
<hr class="foo" id="bar"/>
<hr class="foo" id="bar" >