How to block an element according to its child

[Qrox]

forum/viewtopic.php?f=10&t=10733&p=61956#p61956
I posted this to the wrong forum, please delete the previous one.

What I want to ask is, if I want to block a div element like below, acccording to the id of its child:

Code: Select all

<div>
  <span id="a">a</span>
  <span>b</span>
</div>

how do I write the filter string?
plz tell me if you know. I'd appreciate it.

[John2]

that isn't possible.