jQuery hasClass对我不起作用？

Question

In following code, hasClass doesn't work and result is false in alert. why, what do i do?

Online Demo: http://jsfiddle.net/Fe3CK/

HTML:

<span>
    <div class="adding"></div>
</span>

JS:

alert($('span').hasClass('adding'));

Answer 1

I think you might be misunderstanding what .hasClass does. It checks whether the element itself has one of these classes assigned. From the documentation :

Determine whether any of the matched elements are assigned the given class.

If you want to check whether the element contains an element with that class, use .has :

Reduce the set of matched elements to those that have a descendant that matches the selector or DOM element.

alert($('span').has('.adding').length > 0);

Answer 2

You need:

alert($('span div').hasClass('adding'));

since your span does not have any class adding . Only the child div of your span has it.

Updated Fiddle

Note: Only inline elements may be contained within inline elements. span is an inline element so block level elements like div or p cannot appear within a span.

Hence, <div> inside <span> tag is not a valid HTML5 markup so you should use <div> instead of <span> in this case.

Answer 3

You have to select div not span , as div has class of 'adding'

alert($('div').hasClass('adding'));

Demo

Answer 4

如果要检查任何span的孩子都上过课，则可以这样尝试；

alert($('span').children().hasClass('adding'));

Answer 5

范围内的div不是一个好习惯，并且您的范围内没有任何添加的类，添加是其子对象的类，因此请使用

alert($('span').children().hasClass('adding'));