title: how can i create my own HTML tag?
body: <p>how can i create my own html tags in HTML or HTML5 so i can make my own html tag and css library
  such as </p>
  
  <pre><code>&lt;mymenu&gt; ul li or some text &lt;/mymenu&gt;
  
  &lt;heading&gt; Yeah My Own Heading&lt;/heading&gt;
  </code></pre>
  
  <p>is their a way to do that? if yeah please tell me how i am really curious about it. and tell me what problems should i will be having after making my personalize tags (if you know any) .</p>