Style of WebTextField HelpTag?

I don’t like the yellow background with black text that is the style of the hover over provided when you provide help text.
Can the style of the help text be changed? Globally is ok…

The help tags mechanism uses whatever the browser provides. At the moment we don’t have control over that.

If you’d like more control, please file a feature request.

Is the hover over pop up accomplished with java script?

No. It’s accomplished by setting the Title attribute. The browser takes it from there.