HTML 5 with Webforms 2 provides an <input type="range">
which will make the browser generate a native slider for you. Unfortunately all browsers doesn't have support for this, however google has implemented all Webforms 2 controls with js. IIRC the js is intelligent enough to know if the browser has implemented the control, and triggers only if there is no native implementation.
From my point of view it should be considered best practice to use the browsers native controls when possible.