Multicolor Text Highlighting in a Textarea or Text Input

I'd like to set text in a textarea or text input using different colors (one or the other is fine, I don't need both). Think of something like simple syntax highlighting. So, let's say I have some keywords defined. I'd like those words to be colored a different color as the user types into the textarea or text input

I understand this needs to be some combination of CSS, Javascript, and maybe some pixie dust. I wondering which direction I need to dig into to find out how this can be done.

Thank you

No, you can't do this in a textarea or text input. Any CSS text-related property will affect the whole text within the the textarea/input. You'll need an editable element or document to achieve syntax highlighting. Example (works in all recent browsers; the last major browser not to support contenteditable was Firefox 2.0):

<code contenteditable="true">
  <span style="color: blue">var</span> foo = <span style="color: green">"bar"</span>;
</code>

Are you finding this?

Use jQuery.colorfy

Code: https://github.com/cheunghy/jquery.colorfy

Demo: http://cheunghy.github.io/jquery.colorfy/

Screencast: https://www.youtube.com/watch?v=b1Lu_qKrLZ0