If vs. while in specific JavaScript code

Question

Why does the author of Test-Driven JavaScript Development (Christian Johansen) use the while statement instead of the if statement in the code below?

function getEventTarget(event) {
    var target = event.target || event.srcElement;

    while (target && target.nodeType != 1) {
        target = target.parentNode;
    }

    return target;
}

Answer 1

Because the author wanted to keep walking up the tree until the correct node type was found; it might not be the immediate parent.

However, in this case it makes no sense, as parentNode will always return an element in real-world usage (or a Document).