How can I select an element with multiple classes in jQuery?

If you want to match only elements with both classes (an intersection, like a logical AND), just write the selectors together without spaces in between:

$('.a.b')

The order is not relevant, so you can also swap the classes:

$('.b.a')

So to match a div element that has an ID of a with classes b and c, you would write:

$('div#a.b.c')

(In practice, you most likely don't need to get that specific, and an ID or class selector by itself is usually enough: $('#a').)

You can do this using the filter() function:

$(".a").filter(".b")

For the case

<element class="a">
  <element class="b c">
  </element>
</element>

You would need to put a space in between .a and .b.c

$('.a .b.c')