Css – Dojo TabContainer with styling in Internet Explorer

2015 update: the flexbox approach

There are two other answers briefly mentioning flexbox; however, that was more than two years ago, and they don't provide any examples. The specification for flexbox has definitely settled now.

Note: Though CSS Flexible Boxes Layout specification is at the Candidate Recommendation stage, not all browsers have implemented it. WebKit implementation must be prefixed with -webkit-; Internet Explorer implements an old version of the spec, prefixed with -ms-; Opera 12.10 implements the latest version of the spec, unprefixed. See the compatibility table on each property for an up-to-date compatibility status.

(taken from https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Flexible_boxes)

All major browsers and IE11+ support Flexbox. For IE 10 or older, you can use the FlexieJS shim.

To check current support you can also see here: http://caniuse.com/#feat=flexbox

Working example

With flexbox you can easily switch between any of your rows or columns either having fixed dimensions, content-sized dimensions or remaining-space dimensions. In my example I have set the header to snap to its content (as per the OPs question), I've added a footer to show how to add a fixed-height region and then set the content area to fill up the remaining space.

html,
body {
  height: 100%;
  margin: 0;
}

.box {
  display: flex;
  flex-flow: column;
  height: 100%;
}

.box .row {
  border: 1px dotted grey;
}

.box .row.header {
  flex: 0 1 auto;
  /* The above is shorthand for:
  flex-grow: 0,
  flex-shrink: 1,
  flex-basis: auto
  */
}

.box .row.content {
  flex: 1 1 auto;
}

.box .row.footer {
  flex: 0 1 40px;
}

<!-- Obviously, you could use HTML5 tags like `header`, `footer` and `section` -->

<div class="box">
  <div class="row header">
    <p><b>header</b>
      <br />
      <br />(sized to content)</p>
  </div>
  <div class="row content">
    <p>
      <b>content</b>
      (fills remaining space)
    </p>
  </div>
  <div class="row footer">
    <p><b>footer</b> (fixed height)</p>
  </div>
</div>

In the CSS above, the flex property shorthands the flex-grow, flex-shrink, and flex-basis properties to establish the flexibility of the flex items. Mozilla has a good introduction to the flexible boxes model.

You don't need JavaScript for this! Here is a cross-browser solution:

See this example! - It works in Chrome/FF/IE - (IE10/9/8/7)

The best approach would be to have a custom label element with a for attribute attached to a hidden file input element. (The label's for attribute must match the file element's id in order for this to work).

<label for="file-upload" class="custom-file-upload">
    Custom Upload
</label>
<input id="file-upload" type="file"/>

As an alternative, you could also just wrap the file input element with a label directly: (example)

<label class="custom-file-upload">
    <input type="file"/>
    Custom Upload
</label>

In terms of styling, just hide¹ the input element using the attribute selector.

input[type="file"] {
    display: none;
}

Then all you need to do is style the custom label element. (example).

.custom-file-upload {
    border: 1px solid #ccc;
    display: inline-block;
    padding: 6px 12px;
    cursor: pointer;
}

¹ - It's worth noting that if you hide the element using display: none, it won't work in IE8 and below. Also be aware of the fact that jQuery validate doesn't validate hidden fields by default. If either of those things are an issue for you, here are two different methods to hide the input (1, 2) that work in these circumstances.