The vdf.getControl will give you the JavaScript control object of the AJAX Library which provides the API's described in the documentation (for a grid look at the vdf.deo.Grid class). This JavaScript control has references to the DOM (most AJAX Controls have a property 'eElement' that points to their main DOM element) and manipulates the DOM objects to which it belongs.

It is advised to use the AJAX Library API's as much as possible when working with AJAX Library control's because manipulating the DOM directly might disturb their behavior. It should be no problem to use JQuery or JQuery controls withing the same page but it might give problems if you use them on the same elements.