Check if class already assigned before adding

jquery addclass
Muleskinner picture Muleskinner · Sep 13, 2011 · Viewed 41.4k times · Source

In jQuery, is it recommended to check if a class is already assigned to an element before adding that class? Will it even have any effect at all?

For example:

<label class='foo'>bar</label>

When in doubt if class baz has already been assigned to label, would this be the best approach:

var class = 'baz';
if (!$('label').hasClass(class)) {
  $('label').addClass(class);
}

or would this be enough:

$('label').addClass('baz');

Answer

jmar777 picture jmar777 · Sep 13, 2011

Just call addClass(). jQuery will do the check for you. If you check on your own, you are doubling the work, since jQuery will still run the check for you.

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