How can I find a previous sibling's child?

Given this structure:

<div cla开发者_Go百科ss="a">
  <div class="b">
  </div>
</div>
<div class="c"></div>
<div class="d"></div>

...And a reference to d, how would I use jQuery to select the element with class b?

The simplest way is:

$('.d').siblings('.a').find('.b')

d_object.parent().siblings('div.a').children('div.b')

I assume you gave them class names just to reference them in your question.

$('.d').siblings(':first').children()

jsFiddle.

Otherwise you could use...

$('.d').siblings('.a').children('.b')

$('.d').siblings('div.a:first').find('.b')