How to add CSS if element has more than one child?

Question

I have td tags and a several div inside td:

Answer 1

i think there is no way to add the 10px margin to each div inside a td without the use of css3.

so a solution would be to use javascript and check if there are more than 1 div's inside the td and then if yes add a special class.

css

.myMarginClass div{
 margin-bottom:10px;
}

js

var td=document.getElementsByTagName('td'),
l=td.length;
while(l--){
 if(td[l].getElementsByTagName('div').length>1){
  td[l].className='myMarginClass';
 }
}

else for modern browsers the proper solution is the :only-child proposed by @mikel