How to stick footer to bottom of screen and prevent middle section extending below footer?

问题

I've been trying to set three columns to 100% height of a main content area with a header and footer on the top and bottom.

The desired behavior is:

When the content does not take up the screen, the footer is at the bottom of the screen, and the middle area stretches to fill the middle space.
When the content takes up more than the screen, the footer is at the bottom of the content, not the screen.

I ended up going with the table and table-cell solution, but the middle section extends below the footer - which causes an unnecessary scrollbar to appear, see:

https://jsfiddle.net/rwone/rqmrxfbp

A similar question was asked here.

Relevant HTML

<div id="container">
    <div id="left_col"></div>
    <div id="main_content"></div>
    <div id="right_col"></div>
</div>
<div id="footer"></div>

CSS

#container {
    display: table;
    width: 100%;
    height: 100%;
}

#left_col {
    background: orange;
    display: table-cell;
    width: 15%;
}

#main_content {
    background: #ff0;
    display: table-cell;
}

#right_col {
    background: green;
    display: table-cell;
    width: 15%;
}

#footer {
    background: #3a3a3a;
    height: 200px;
    position: absolute;
    width: 100%;
    bottom: 0;
}

回答1:

Continued on your choice to using display: table, where I added the proper markup instead of using anonymous table elements.

In the future one don't know how those might render so I think have them added will make sure they work as intended (and make it easier to read the markup).

html, body{
  height: 100%;
  margin: 0;
}
.tbl{
  display:table;
}
.row{
  display:table-row;
}
.row.expanded{
  height: 100%;
}
.cell{
  display:table-cell;
}
.container,
.content{
  width: 100%;
  height: 100%;
}
.header {
  background: #0099cc none repeat scroll 0 0;
  height: 75px;
}
.menu {
  border-bottom: 1px solid #555;
  border-top: 1px solid #555;
  background-color: #999;
  height: 0;
}
.footer {
  background: #3a3a3a;
  height: 75px;
}

#left_col {
  background: orange none repeat scroll 0 0;
  width: 15%;
}
#main_content {
  background: yellow none repeat scroll 0 0;
}

#right_col {
  background: green none repeat scroll 0 0;
  width: 15%;
}

ul#main_menu {
  margin: 0;
  padding: 0;
  text-align: center;
}
#main_menu li {
  border-right: 1px solid #555;
  display: inline-block;
  margin-right: -4px;    /* might need adjustment based on font size */
  width: 20%;
}
#main_menu li a {
  color: #fff;
  display: block;
  font-family: arial;
  font-size: 15px;
  letter-spacing: 1px;
  line-height: 24px;
  padding: 5px 0;
  text-decoration: none;
}

<div class="tbl container">
  <div class="row">
    <div class="cell header">
    </div>
  </div>
  <div class="row">
    <div class="cell menu">
      <ul id="main_menu">
        <li><a href="/">one</a></li><li><a href="/two.html">two</a></li><li><a href="/three.html">three</a></li><li><a href="/four.html">four</a></li><li><a href="/five.html">five</a></li>
      </ul>
    </div>
  </div>
  <div class="row expanded">
    <div class="cell">
      <div class="tbl content">
        <div class="row">
          <div id="left_col" class="cell">
            long content <br>long content <br>long content <br>long content <br>
            long content <br>long content <br>long content <br>long content <br>
            long content <br>long content <br>long content <br>long content <br>
            long content last
          </div>
          <div id="main_content" class="cell"></div>
          <div id="right_col" class="cell"></div>
        </div>
      </div>
    </div>
  </div>
  <div class="row">
    <div class="cell footer">
    </div>
  </div>
</div>

With flexbox the markup can be cleaned up a little

html, body{
  margin: 0;
}
.flex{
  display:flex;
}
.flex.column {
  flex-direction: column
}
.flexitem{
}
.container{
  min-height: 100vh;
}
.header {
  background: #0099cc none repeat scroll 0 0;
  height: 75px;
}
.menu {
  border-bottom: 1px solid #555;
  border-top: 1px solid #555;
  background-color: #999;
}
.content,
#main_content{
  flex: 1;
}
.footer {
  background: #3a3a3a;
  height: 75px;
}

#left_col {
  background: orange none repeat scroll 0 0;
  width: 15%;
}
#main_content {
  background: yellow none repeat scroll 0 0;
}

#right_col {
  background: green none repeat scroll 0 0;
  width: 15%;
}

ul#main_menu {
  margin: 0;
  padding: 0;
  text-align: center;
}
#main_menu li {
  list-style-type: none;
  border-right: 1px solid #555;
  width: 20%;
}
#main_menu li a {
  color: #fff;
  display: block;
  font-family: arial;
  font-size: 15px;
  letter-spacing: 1px;
  line-height: 24px;
  padding: 5px 0;
  text-decoration: none;
}

<div class="flex column container">
  <div class="header">
  </div>
  <div class="menu">
    <ul id="main_menu" class="flex">
      <li><a href="/">one</a></li><li><a href="/two.html">two</a></li><li><a href="/three.html">three</a></li><li><a href="/four.html">four</a></li><li><a href="/five.html">five</a></li>
    </ul>
  </div>
  <div class="flex content">
    <div id="left_col">
      long content <br>long content <br>long content <br>long content <br>
      long content <br>long content <br>long content <br>long content <br>
      long content <br>long content <br>long content <br>long content <br>
      long content last
    </div>
    <div id="main_content"></div>
    <div id="right_col"></div>
  </div>
  <div class="footer">
  </div>
</div>

回答2:

Hope this works.

#footer {
background: #3a3a3a;
height: 200px;
width: 100%;
position:absolute;
}

来源：https://stackoverflow.com/questions/37631308/how-to-stick-footer-to-bottom-of-screen-and-prevent-middle-section-extending-bel

标签

html

css3