[ars]

> But you'd have to load N iframes for N vote buttons on page load.

No you don't. Use a FORM with a target of the iframe, make each arrow an <input type=image name="id#">

One form can cover all the arrows at once. Or you can have a form per set of arrows. Either way you only need one iframe.

Making it hide is a bit more complicated:

One way is have it hide on focus using visiblity, then set a very long transition in the CSS rules to unhide.