i just want to know is this ok if i usethis stucture:<header>  <h1>Luke</h1>  <ul>    <li><a href=#>Sign In</a></li>    <li><a href=#>Sign Up</a></li>  </ul></header>instead of this ?<div id=header>  <div id=luke>     <h1>Luke</h1>  </div>  <div id=navbar>     <ul>         <li><a href=#>Sign In</a></li>         <li><a href=#>Sign Up</a></li>     </ul>  </div></div>and if not, i want to know why ? and also i want to know which one is SEO Friendly and why?
using header tag for menu is SEO Friendly?
seo;html5