Hii @kartik,
Using javascript
<script>
  $("a[href='#top']").click(function() {
     $("html, body").animate({ scrollTop: 0 }, "slow");
     return false;
  });
</script>
However you don't need javascript  to do this. A standard HTML tag will suffice..
<a href="#top">go top</a>
Thank You!!