How to highlight changes/difference in one text paragraph from the other?

Question

Is it possible to highlight the modifications in one text paragraph from the other?

For example, there are 3 text fields in a database. Non-admin users can edit the text

Answer 1

This is an old thread but thought I'd catalog my findings.

If you want to use raw php, this is by far the simplest, fastest, and most effective solution I've found: http://paulbutler.org/archives/a-simple-diff-algorithm-in-php/

From what I can tell, the author of the above code is using an algorithm outlined in this article: http://www.codeproject.com/Articles/6943/A-Generic-Reusable-Diff-Algorithm-in-C-II

Basic description of what's happening (taken from the article):

• Find the current Longest Matching Sequence (LMS) of items.
• Store this LMS in a results pile.
• Process all data left above the LMS using recursion.
• Process all data left below the LMS using recursion.

Works like a charm!