Question

OK, I want to set margin for the second div on the page using

$('div#superid:nth-child(2)').css('margin-left', '10px');

Everything works find, I’ve reached the goal. But, I want that rule applied ONLY if this div contains at least one input radio with name superchild.
So, the rule above should apply to:

<div id="superid">
   <div>some text
   </div>
   <div>
    <input type="radio"  name="superchild" value="2010">
    <input type="radio"  name="superchild" value="2010">
   </div>
</div>

because it has at least one input radio with name="superchild"
What’s the best way to do that?

Answer 1

You could also use the filter method.
The script below selects every div in the #superid-div, which has at least one input field of type radio and name superchild. Then it adds the desired css to the selected divs.

$('div#superid > div').filter( function(index,elem) {
    return $(this).find('input[type=radio][name=superchild]').length > 0;
}).css('margin-left', '10px');

jsFiddle

If you want do add this style ONLY to the second div, use your selector instead. But I thought my script covers the desired behaviour better.