滚动显示页脚

是的，这是纯css。只需要输入position: fixed和z-index: 0，就像:

.footer {    
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 0;
}

和主要含量position: relative和z-index: 1

.main-content {    
    position: relative;
    z-index: 1;
}

这里是jsFiddle: https://jsfiddle.net/7uv2fzvp/11/

关于JSFiddle的演示

// Hide Header on on scroll down
var didScroll;
var lastScrollTop = 0;
var delta = 5;
var navbarHeight = $('footer').outerHeight();
$(window).scroll(function(event) {
  didScroll = true;
});
setInterval(function() {
  if (didScroll) {
    hasScrolled();
    didScroll = false;
  }
}, 250);
function hasScrolled() {
  var st = $(this).scrollTop();
  // Make sure they scroll more than delta
  if (Math.abs(lastScrollTop - st) <= delta)
    return;
  // If they scrolled down and are past the navbar, add class .nav-up.
  // This is necessary so you never see what is "behind" the navbar.
  if (st > lastScrollTop && st > navbarHeight) {
    // Scroll Down
    $('footer').removeClass('nav-down').addClass('nav-up');
  } else {
    // Scroll Up
    if (st + $(window).height() < $(document).height()) {
      $('footer').removeClass('nav-up').addClass('nav-down');
    }
  }
  lastScrollTop = st;
}

* {
  margin: 0;
  padding: 0;
}
body {
  font: 15px/1.3 'PT Sans', sans-serif;
  color: #5e5b64;
  position: relative;
  z-index: 0;
}
a,
a:visited {
  outline: none;
  color: #389dc1;
}
a:hover {
  text-decoration: none;
}
section,
footer,
header,
aside {
  display: block;
}
#main {
  position: relative;
  z-index: 1;
  background-color: #fff;
  padding: 120px 0 600px;
  box-shadow: 0 3px 3px rgba(0, 0, 0, 0.2);
}
#main .tzine-logo {
  width: 336px;
  height: 121px;
  margin: 0 auto 90px;
  text-indent: -999px;
  overflow: hidden;
  display: block;
}
h1 {
  font: bold 48px 'PT Sans Narrow', sans-serif;
  color: #5e5b64;
  text-align: center;
  padding-bottom: 300px;
  position: relative;
}
h1:after {
  content: '';
  width: 45px;
  height: 70px;
  position: absolute;
  left: 50%;
  bottom: -85px;
  margin-left: -23px;
}
footer {
  height: 245px;
  color: #ccc;
  font-size: 12px;
  position: relative;
  z-index: -2;
  background-color: #31353a;
}
footer > ul {
  width: 960px;
  position: fixed;
  left: 50%;
  bottom: 0;
  margin-left: -480px;
  padding-bottom: 60px;
  z-index: -1;
}
footer > ul > li {
  width: 25%;
  float: left;
}
footer ul {
  list-style: none;
}
footer > ul > li ul li {
  margin-left: 43px;
  text-transform: uppercase;
  font-weight: bold;
  line-height: 1.8;
}
footer > ul > li ul li a {
  text-decoration: none !important;
  color: #7d8691 !important;
}
footer > ul > li ul li a:hover {
  color: #ddd !important;
}
footer p {
  width: 90%;
  margin-right: 10%;
  padding: 9px 0;
  line-height: 18px;
  background-color: #058cc7;
  font-weight: bold;
  font-size: 14px;
  color: #fff;
  text-transform: uppercase;
  text-shadow: 0 1px rgba(0, 0, 0, 0.1);
  box-shadow: 0 0 3px rgba(0, 0, 0, 0.3);
  margin-bottom: 20px;
  opacity: 0.9;
  cursor: default;
  -webkit-transition: opacity 0.4s;
  -moz-transition: opacity 0.4s;
  transition: opacity 0.4s;
}
footer > ul > li:hover p {
  opacity: 1;
}
footer p:before {
  content: '';
  display: inline-block;
  width: 16px;
  height: 18px;
  margin: 0 12px 0 15px;
  vertical-align: text-bottom;
}
/*-------------------------
	The different colors
--------------------------*/
footer p.home {
  background-color: #0096d6;
  background-image: -webkit-linear-gradient(top, #0096d6, #008ac6);
  background-image: -moz-linear-gradient(top, #0096d6, #008ac6);
  background-image: linear-gradient(top, #0096d6, #008ac6);
}
footer p.home:before {
  background-position: 0 -110px;
}
footer p.services {
  background-color: #00b274;
  background-image: -webkit-linear-gradient(top, #00b274, #00a46b);
  background-image: -moz-linear-gradient(top, #00b274, #00a46b);
  background-image: linear-gradient(top, #00b274, #00a46b);
}
footer p.services:before {
  background-position: 0 -129px;
}
footer p.reachus {
  background-color: #d75ba2;
  background-image: -webkit-linear-gradient(top, #d75ba2, #c75496);
  background-image: -moz-linear-gradient(top, #d75ba2, #c75496);
  background-image: linear-gradient(top, #d75ba2, #c75496);
}
footer p.reachus:before {
  background-position: 0 -89px;
}
footer p.clients {
  background-color: #e9ac40;
  background-image: -webkit-linear-gradient(top, #e9ac40, #d89f3b);
  background-image: -moz-linear-gradient(top, #e9ac40, #d89f3b);
  background-image: linear-gradient(top, #e9ac40, #d89f3b);
}
footer p.clients:before {
  background-position: 0 -69px;
}

   <script type="text/javascript" src="http://cdnjs.cloudflare.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script><script type="text/javascript" src="http://cdn.tutorialzine.com/misc/enhance/v2.js"></script>
<div id="main">
  <h1>slide-out footer.</h1>
</div>
<footer>
  <ul>
    <li>
      <p>Test</p>
    </li>
    <li>
      <p>Test</p>
    </li>
    <li>
      <p>Test</p>
    </li>
    <li>
      <p>Test</p>
    </li>
  </ul>
</footer>

有一篇非常好的文章详细解释了z-index，我强烈建议您在继续阅读之前先阅读。

嗯，这是我找到的一个代码。https://codepen.io/cerebrovinny/pen/vYdJJVa

HTML:

向下滚动并向滑出页脚打招呼

<footer><p>Here i am. Ready to use me for navigation lists or other content.</p></footer>

* {margin:0; padding:0; font-family: Helvetica; font-weight:bold; font-size: 1.4em;text-align:center;}
    section {width:100%; height:1024px; margin: 0 0 360px 0;background-color:#ececec; position:relative; z-index:2; color: #1e2024;}
    footer {width:100%; height:360px;background-color:#262932; position:fixed; bottom:0; left:0; color: #ef4a4a; text-align:center; z-index:0;}
    p {padding: 1em 4em;}