Html – Browser white space rendering

htmlwhitespace

Recently I was editing someone else's code and I noticed that spaces were used something like the following:

<div>Some text &nbsp; &nbsp; &nbsp; Some other text</div>

I naturally assumed that the browser would combine the extra spaces, so this is really just four spaces. Testing this out though – it is actually 7 spaces (in chrome at least)! This is because the browser renders both the in between spaces and the nbsp; spaces as well.

So my question is, when will the browser render white space and when won't it? In other words, when will a single space character be rendered vs ignored?

JSFiddle Demo: http://jsfiddle.net/L7x7t/3/

Best Answer

Browsers only collapse consecutive regular space characters. Text rendering is mostly governed by the CSS spec rather than the HTML spec (with exceptions); with respect to whitespace collapsing, section 16.6.1 of CSS2.1 has the details. Specifically:

any space (U+0020) following another space (U+0020) — even a space before the inline, if that space also has 'white-space' set to 'normal', 'nowrap' or 'pre-line' — is removed.

Since there's a non-breaking space separating every two space characters that would otherwise be consecutive (and non-breaking spaces are not considered "regular" space characters), the browser has no opportunity to collapse any of them, and so must render all of them in sequence.

The behavior across browsers is mostly identical, except for a nasty bug in Chrome regarding the part about "a space before the inline".

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.

Best Answer

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2015 update: the flexbox approach

Working example

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