Suppose you have comment section at the very bottom of your page, so while you load the page you have to scroll down to comment section using jquery scrollTop.
Here is a sample html code with jquery for your help, it will automatically scroll to comment area with a nice smooth animation.
<html>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
<script>
$(document).ready(function () {
$('html, body').animate({
scrollTop: $("#commentArea").offset().top
}, 2000);
});
</script>
<button id="click">Click me</button>
<div id="mainArea" style="height: 1000px; width: 100px">
Main Section
</div>
<br />
<div id="commentArea" style="height: 1000px; width: 100px">
Comment Section
</div>
</html>