How to use

$("nav").find("a").click (e) ->
    e.preventDefault()
    section = $(this).attr "href"
    $("html, body").animate
        scrollTop: $(section).offset().top

$("nav").find("a").click(function(e) {
    e.preventDefault();
    var section = $(this).attr("href");
    $("html, body").animate({
        scrollTop: $(section).offset().top    });});

<nav>
    <a href="#welcome">Welcome</a>
    <a href="#about">About</a>
    <a href="#section3">Section 3</a>
</nav>
<div id="welcome">Welcome to this website</div>
<div id="about">About this website, and such</div>
<div id="section3">The third section</div>