Is detecting scrollbar presence with jQuery still difficult?

I know that detecting scrollbar presence is supposed to be one of those elusive things that we should all have to suffer through. What I've read so far is that you can't really detect scrollbar pre开发者_JAVA技巧sence, only use hints in the DOM to know if they may be present, and it can't be done in less than 30 lines of code.

This sounds a little impossible to me now that we're in 2010. Does jQuery have a cross-browser reliable solution that takes care of this and works at least most of the time? Any help please, I'm pulling my hair, half of it is already on the floor.

Probably not as elegant as you were hoping for but this is an adequate adaption from a script I recently wrote to calculate viewport height.

Logically you'd want to call this function on document ready and window resize.

It also deals with inconsistencies that you'd encounter in Opera ^{(line 2)} and IE7 ^{(line 6)}.

function scrollbar() {
    var viewportHeight = window.innerHeight ? window.innerHeight : $(window).height();

    if (jQuery.browser.msie) {
        if(parseInt(jQuery.browser.version) == 7) {
            viewportHeight -= 3;
        }
    }

    if(viewportHeight <= $('#wrapper').height()) {
        return true;
    } else {
        return false;
    }
}