title: Is <BUTTON> functionally equivalent to <SPAN>?
body: <p>It seems to me that <code>&lt;button&gt;</code> in HTML5 is essentially a <code>&lt;span&gt;</code> with some default styling and possibly slightly different DTD rules... (You can't have a <code>&lt;button&gt;</code> in a <code>&lt;button&gt;</code> or?)</p>
  
  <p>Is my understanding correct? And other than for declarative purposes and default styling, is there any reason to use the <code>&lt;button&gt;</code> tag anymore?</p>