div with dynamic min-height based on browser window height

Question

I have three div elements: one as a header, one as a footer, and a center content div.
the div in the center needs to expand automatically with content, but I would like a min-height such that the bottom div always at least reaches the bottom of the window, but is not fixed there on longer pages.

For example:

<div id="a" style="height: 200px;">
  <p>This div should always remain at the top of the page content and should scroll with it.</p>
</div>
<div id="b">
  <p>This is the div in question. On longer pages, this div needs to behave normally (i.e. expand to fit the content and scroll with the entire page). On shorter pages, this div needs to expand beyond its content to a height such that div c will reach the bottom of the viewport, regardless of monitor resolution or window size.
</div>
<div id="c" style="height: 100px;">
  <p>This div needs to remain at the bottom of the page's content, and scroll with it on longer pages, but on shorter pages, needs to reach the bottom of the browser window, regardless of monitor resolution or window size.</p>
</div>

Answer 1

Just look for my solution on jsfiddle, it is based on csslayout

html,
body {
  margin: 0;
  padding: 0;
  height: 100%; /* needed for container min-height */
}
div#container {
  position: relative; /* needed for footer positioning*/
  height: auto !important; /* real browsers */
  min-height: 100%; /* real browsers */
}
div#header {
  padding: 1em;
  background: #efe;
}
div#content {
  /* padding:1em 1em 5em; *//* bottom padding for footer */
}
div#footer {
  position: absolute;
  width: 100%;
  bottom: 0; /* stick to bottom */
  background: #ddd;
}

<div id="container">

  <div id="header">header</div>

  <div id="content">
    content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>content<br/>
  </div>

  <div id="footer">
    footer
  </div>
</div>

Answer 2

I found this courtesy of ryanfait.com. It's actually remarkably simple.

In order to float a footer to the bottom of the page when content is shorter than window-height, or at the bottom of the content when it is longer than window-height, utilize the following code:

Basic HTML structure:

<div id="content">
  Place your content here.
  <div id="push"></div>
</div>
<div id="footer">
  Place your footer information here.
</footer>

Note: Nothing should be placed outside the '#content' and '#footer' divs unless it is absolutely positioned.
Note: Nothing should be placed inside the '#push' div as it will be hidden.

And the CSS:

* {
  margin: 0;
}
html, body {
  height: 100%;
}
#content {
  min-height: 100%;
  height: auto !important; /*min-height hack*/
  height: 100%;            /*min-height hack*/
  margin-bottom: -4em;     /*Negates #push on longer pages*/
}
#footer, #push {
  height: 4em;
}

To make headers or footers span the width of a page, you must absolutely position the header.
Note: If you add a page-width header, I found it necessary to add an extra wrapper div to #content. The outer div controls horizontal spacing while the inner div controls vertical spacing. I was required to do this because I found that 'min-height:' works only on the body of an element and adds padding to the height.

*Edit: missing semicolon

Answer 3

If #top and #bottom have fixed heights, you can use:

#top {
    position: absolute;
    top: 0;
    height: 200px;
}
#bottom {
    position: absolute;
    bottom: 0;
    height: 100px;
}
#central {
    margin-top: 200px;
    margin-bot: 100px;
}

---

update

If you want #central to stretch down, you could:

• Fake it with a background on parent;
• Use CSS3's (not widely supported, most likely) calc();
• Or maybe use javascript to dynamically add min-height.

With calc():

#central {
    min-height: calc(100% - 300px);
}

With jQuery it could be something like:

$(document).ready(function() {
  var desiredHeight = $("body").height() - $("top").height() - $("bot").height();
  $("#central").css("min-height", desiredHeight );
});

Answer 4

No hack or js needed. Just apply the following rule to your root element:

min-height: 100%;
height: auto;

It will automatically choose the bigger one from the two as its height, which means if the content is longer than the browser, it will be the height of the content, otherwise, the height of the browser. This is standard css.

Answer 5

As mentioned elsewhere, the CSS function calc() can work nicely here. It is now mostly supported. You could use like:

.container
{
    min-height: 70%;
    min-height: -webkit-calc(100% - 300px);
    min-height: -moz-calc(100% - 300px);
    min-height: calc(100% - 300px);
}

Answer 6

You propably have to write some JavaScript, because there is no way to estimate the height of all the users of the page.

Answer 7

It's hard to do this.

There is a min-height: css style, but it doesn't work in all browsers. You can use it, but the biggest problem is that you will need to set it to something like 90% or numbers like that (percents), but the top and bottom divs use fixed pixel sizes, and you won't be able to reconcile them.

 var minHeight = $(window).height() -
                 $('#a').outerHeight(true) -
                 $('#c').outerHeight(true));

if($('#b').height() < minHeight) $('#b').height(minHeight);

I know a and c have fixed heights, but I rather measure them in case they change later.

Also, I am measuring the height of b (I don't want to make is smaller after all), but if there is an image in there that did not load the height can change, so watch out for things like that.

It may be safer to do:

$('#b').prepend('<div style="float: left; width: 1px; height: ' + minHeight + 'px;">&nbsp;</div>');

Which simply adds an element into that div with the correct height - that effectively acts as min-height even for browsers that don't have it. (You may want to add the element into your markup, and then just control the height of it via javascript instead of also adding it that way, that way you can take it into account when designing the layout.)