计数html5数据属性

Question

I'm trying to count how many elements (list) have the html data attribute of 'data-facet', but I'm undefined.

Here is what I have tried:

$('li').data('facet').length;

Any ideas where I've gone wrong?

Answer 1

If data('facet') represents an integer, then that would explain the undefined result (because you can't run .length on an integer). You can fix this by doing $('li').data('facet').toString().length; instead, but that's not going to get you the result you want (instead, it will give you the length of the data-facet value of the first li element).

To get the desired count of li s, do this:

$('li[data-facet]').length

That will give you the number of li element that have the data-facet attribute.