Detect if browser has smooth scrolling feature alr

I have added smooth scrolling to a site of mine using this piece of JavaScript when clicking on hash links.

$('a[href*=#]')
    .click(onAnchorClick);

function onAnchorClick(event)
{
    return ! scrollTo(this.hash);
}


function scrollTo(target)
{
    var e = $(target);
    var y = e.exists() ? e.offset().top : 0;

    if(y == 0 && target != '#top')
        return false;

    if(Math.max($('html').scrollTop(), $('body').scrollTop()) != y)
        $('html,body')
            .animate({scrollTop: y}, 500, function() { location.hash = target; } );
    else
        location.hash = target;

    return true;
}

$.fn.exists = function()
{
    return this.length > 0 ? this : false;
}

Works fantastic in desktop browsers and looks to work fine on at least iOS devices as well. However, on my WinPhone 8 device it was garbage. Scrolling was a mess and didn't even end up where it should. So I decided to not enable it there through an if( ! /Windows Phone 8\.0/.test(navigator.userAgent)).

Now it works well, and seems the browser on the WinPhone actually is smooth scrolling by default, which is great.

But it is of course a bit dumb to have a smooth scroll script active if the browser already does this by default. Is there a way I can detect if a browser already has a smooth scrolling feature enabled?

Yes and no. Unfortunately there are no standards for these types of things. However there are work arounds, one of which you are already doing: browser sniffing.

Basically, that's about as advanced as this kind of detection goes because some browsers don't yet even support smooth scrolling officially or without experimental developments (like Chromium). And standards won't be set unless the majority are on the same page. Not only that but it also comes down to GPU hardware abilities as some devices and computers struggle with smooth scrolling and animations. So technically speaking, even if a browser did support smooth scrolling, who's to say the device or desktop running it can render fast enough to even display the effect. That's another bottle neck.

I believe someday in the future there will be more of a need for browser feature specifications such as this to better improve user interactions, but until that day you're doing it right.