Safest way to remove unwanted whitespace

Question

Hi

I have this HTML string which often has a lot of whitespaces

Example:

<p>All     these words <br />
<strong>All</strong>   <em>these</em>   words
<pre>    All    these words</pre>
</p>

I need to remove them using JavaScript, and have come up with this regEx:

String.replace(/ {2,}/g, '');

Which seems to do the job with replacing unwanted whitespaces, but I want to preserve the whitespaces inside the PRE element.

Is this possible with a regex?

Answer 1

use:

String.replace(/(<pre[\s\S]*?>[\s\S]*?<\/pre>)| {2,}/ig, '$1')

tested in firefox 3

edit:

see test page here: http://ashita.org/StackOverflow/replacetest.html

Answer 2

You can't do this with regular expressions and it's as simple as that.

Regular expressions are a poor choice for this kind of thing. <pre> blocks can contain other tags and so forth. Also what about CSS (either inline or with classes) that uses the white-space: pre property?

HTML and browsers handle white-space just fine. Is this really a problem you need to solve? If you do, you need an HTML parser of some kind.