Default

<button>Submit</button>

disabled

<button disabled>
  Don't submit
</button>

aria-disabled

<button aria-disabled="true">
  Don't submit
</button>

input type=submit

<input type="submit" value="Submit">

input type=image

<input type="image" src="/media/images/button.jpg" alt="Submit">

input type=reset

<input type="reset" value="Reset">

input type=button

<input type="button" value="Show">

with commandfor and command=show-modal

My modal

 
<button commandfor="my-modal" command="show-modal" aria-haspopup="dialog">
  Show modal
</button>

<dialog id="my-modal" closedby="any">
  <button command="close" commandfor="my-modal">close</button>

  <h1>My modal</h1>
</dialog>

with commandfor and command=toggle-popover

My content

<button commandfor="my-content" command="toggle-popover">
  Show modal
</button>

<div id="my-content" popover>
  <h1>My content</h1>
</div>