Yahoo! UI Library

/**
 * Returns a region object for the node
 * @config region
 * @for Node
 * @type Node
 */
Y.Node.ATTRS.region = {
    getter: function() {
        var node = Y.Node.getDOMNode(this),
            region;

        if (node && !node.tagName) {
            if (node.nodeType === 9) { // document
                node = node.documentElement;
            }
        }
        if (node.alert) {
            region = Y.DOM.viewportRegion(node);
        } else {
            region = Y.DOM.region(node);
        }
        return region;
    }
};

/**
 * Returns a region object for the node's viewport
 * @config viewportRegion
 * @type Node
 */
Y.Node.ATTRS.viewportRegion = {
    getter: function() {
        return Y.DOM.viewportRegion(Y.Node.getDOMNode(this));
    }
};

Y.Node.importMethod(Y.DOM, 'inViewportRegion');

// these need special treatment to extract 2nd node arg
/**
 * Compares the intersection of the node with another node or region
 * @method intersect
 * @for Node
 * @param {Node|Object} node2 The node or region to compare with.
 * @param {Object} altRegion An alternate region to use (rather than this node's).
 * @return {Object} An object representing the intersection of the regions.
 */
Y.Node.prototype.intersect = function(node2, altRegion) {
    var node1 = Y.Node.getDOMNode(this);
    if (Y.instanceOf(node2, Y.Node)) { // might be a region object
        node2 = Y.Node.getDOMNode(node2);
    }
    return Y.DOM.intersect(node1, node2, altRegion);
};

/**
 * Determines whether or not the node is within the giving region.
 * @method inRegion
 * @param {Node|Object} node2 The node or region to compare with.
 * @param {Boolean} all Whether or not all of the node must be in the region.
 * @param {Object} altRegion An alternate region to use (rather than this node's).
 * @return {Object} An object representing the intersection of the regions.
 */
Y.Node.prototype.inRegion = function(node2, all, altRegion) {
    var node1 = Y.Node.getDOMNode(this);
    if (Y.instanceOf(node2, Y.Node)) { // might be a region object
        node2 = Y.Node.getDOMNode(node2);
    }
    return Y.DOM.inRegion(node1, node2, all, altRegion);
};