SO jQuery Fiddle
Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5
by Nick Craver
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<div>
123 test 1235123, 123, 123, 123-09123-990
</div>
CSS
span { color: red; }
JavaScript
$("div").html(function() { return $(this).text().replace(/(\d+)/g,"<span>$1</span>"); });