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How to show a comparison of 2 html text blocks

Asked 2009-09-01T05:02:58.840
10

I need to take two text blocks with html tags and render a comparison - merge the two text blocks and then highlight what was added or removed from one version to the next.

I have used the PEAR Text_Diff class to successfully render comparisons of plain text, but when I try to throw text with html tags in it, it gets UGLY. Because of the word and character-based compare algorithms the class uses, html tags get broken and I end up with ugly stuff like <p><span class="new"> </</span>p>. It slaughters the html.

Is there a way to generate a text comparison while preserving the original valid html markup?

Thanks for the help. I've been working on this for weeks :[

This is the best solution I could think of: find/replace each type of html tag with 1 special non-standard character like the apple logo (opt shift k), render the comparison with this kind of primative markdown, then revert the non-standard characters back into tags. Any feedback?

php html comparison compare pear
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1 Answer

-1

Try running your HTML blocks through this function first:

htmlentities();

That should convert all of your "<"'s and ">"'s into their corresponding codes, perhaps fixing your problem.

//Example:
$html_1 = "<html><head></head><body>Something</body></html>"
$html_2 = "<html><head></head><body><p id='abc'>Something Else</p></body></html>"

//Below code taken from http://www.go4expert.com/forums/showthread.php?t=4189.
//Not sure if/how it works exactly

$diff = &new Text_Diff(htmlentities($html_1), htmlentities($html_2));
$renderer = &new Text_Diff_Renderer();
echo $renderer->render($diff);
answered 2009-09-01T05:12:28.307

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