Redirect a div id to other div id in a same page?

Someone Please help me in redirecting a user from one div id to other div id afte开发者_StackOverflowr the particular div id is enabled it should redirect after 3 seconds to other div id

HTML

<div id="a">a</div>
<div id="b">b</div>

JavaScript

window.location.hash = 'b';