在添加之前检查班级是否已经分配 [英] Check if class already assigned before adding

问题描述

在jQuery中，建议在添加该类之前先检查是否已将一个类分配给某个元素吗?会不会有任何效果?

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?

例如:

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

不确定是否已将类baz分配给label时，这是最好的方法:

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);
}

否则就足够了:

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

推荐答案

只需调用addClass(). jQuery将为您完成检查.如果您自己进行检查，那么您将使工作加倍，因为jQuery会仍然为您运行检查.

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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