This is a AsyncLink demo,We implement it use JavaScript now. How about browser implements this? Use a new '' tag or modify '' tag?

<a href="json.php" target="#foo" async="true" history="true" where="replace">asynclink</a>
<async url="json.php" target="#foo" history="true" where="replace">asynclink</async>

target represents html dom async represents this is a async link history represents browser will add a historyhash for this asynclink where represents where to append the async content "replace"|"first"|"last"