structure document HTML

Structure document HTML.
Element =<opening tag> + document +</closing tag>
Example :
<p>Structure document HTML</p>.is element.
or
Element =<opening tag 1> + document 1 +<opening tag 2>+document 2+</closing tag></closing tag 1>
Example:
<p>Structure document<em> HTML</em></p>
or
Element:=<opening tag +atributes> + document +</closing tag>
Attributes is name attribute and value attribute