Making the main scrollbar always visible

Question

What CSS is required to make the browser's vertical scrollbar remain visible when a user visits a web page (when the page hasn't enough content to trigger the scrollbar's activation)?

Answer 1

html {
    overflow: -moz-scrollbars-vertical; 
    overflow-y: scroll;
}

This make the scrollbar always visible and only active when needed.

Update: If the above does not work the just using this may.

html {
    overflow-y:scroll;
}