Remove all child elements of a DOM node in JavaScript

How would I go about removing all of the child elements of a DOM node in JavaScript?

Say I have the following (ugly) HTML:

<p id="foo">
    <span>hello</span>
    <div>world</div>
</p>

And I grab the node I want like so:

var myNode = document.getElementById("foo");

How could I remove the children of foo so that just <p id="foo"></p> is left?

Could I just do:

myNode.childNodes = new Array();

or should I be using some combination of removeElement?

I’d like the answer to be straight up DOM; though extra points if you also provide an answer in jQuery along with the DOM-only answer.