1<div class="first"><button type="button" onclick="smoothScroll(document.getElementById('second'))">Click Me!</button></div>
2<div class="second" id="second">Hi</div>
3

1$("button").click(function() {
2    $('html,body').animate({
3        scrollTop: $(".second").offset().top},
4        'slow');
5});
6
7// example: http://jsfiddle.net/ryXFt/3/

1$(window).scroll(function() {
2    $('html, body').animate({
3        scrollTop: $("#myDiv").offset().top
4    }, 2000);
5});