Get all elements without child node in jQuery

I need to select elements without child node (including text since in <p> text is a child node).

I used empty, but it also consider space as child node.

Example:

Markup:

 <span> </span>
 <span></span>

Script:

$("span:empty").html("this was empty!");

Unfortunately, only the second element were selected and changed since the first element has space and it was considered child node.

How do I select elements without child node? I want to consider a space as nothing. Preferably, I want the code not to use loop to select them, there might be other ways.

How about

$("span:not(:has(*))")

Selects all spans that have no children.

Explanation

The :has() selector "selects elements which contain at least one element that matches the specified selector." The wildcard * means all elements.

The expression $('div:has(p)') matches a <div> if a <p> exists anywhere among its descendants, not just as a direct child.

The :not() selector "selects all elements that do not match the given selector."

In this case, :has() selects everything and then we use :not() to find the elements that don't match "everything"... in other words, nothing.

Demo

$.expr[":"]["no-children"] = function( elem ) {
    return !elem.firstChild || !$.trim(""+ elem.firstChild.nodeValue);
};
$("span:no-children").html("this was empty");

​

http://jsfiddle.net/k5eTS/6/

There was a surprising "feature" with jQuery's $.trim that converts null to "" while I was expecting "null". Converting to string manually fixes this.