Determine if event target is a descendant of a DOM node

targetIsDescendant.js

/**
 * Determine if event target is a descendant of a DOM node
 * @param {Object} event - The event object
 * @param {Element} parent - The DOM node to check if event target is equal to or a descendant of
 * @return {Boolean}
 */
function targetIsDescendant(event, parent) {
    var node = event.target || null;
    while (node !== null) {
        if (node === parent) return true;
        node = node.parentNode;
    }
    return false;
}