Parsing a class out of classname attr
by JAAulde
HTML
<span class="a-class another-class test-top-left"></span>
JavaScript
var wholeclass = $('span').attr('class'),
pattern = /(?:^|\s)test-[a-z0-9_-]+(?:\s|$)/mi,
matches = wholeclass.match(pattern),
extractedclass = $.trim(matches[0]);
alert(extractedclass);