In HTML5 there is no difference, other than XML conformance which is not required when the document is served as
As it stands now, text/html is the de facto MIME type, and therefore the default in which case, HTML 4 becomes the core specification, and valid HTML5. There are some exceptions to this, such as deprecated or obsolete tags and attributes.
is valid, as is,
The last is the specified form in XHTML, the recommendations of which HTML5 is a refinement. To be backward compatible HTML5 needed to support both HTML 4 and XHTML. It was XHTML that demanded the
/ in self-closing tags, not HTML 4. In fact pre-XHTML the term had not even been thought of yet.
<BR> is a void element in HTML 4.
Bottom line, unless the lesson checker expects the
/, it can be left out of all tags, this especially since as stated earlier, the page is served as text/html unless otherwise specified. Further reading…
XML Conforming Markup Languages.