I've used next function to get scrollbar height/width:
function getBrowserScrollSize(){
var css = {
"border": "none",
"height": "200px",
"margin": "0",
"padding": "0",
"width": "200px"
};
var inner = $("<div>").css($.extend({}, css));
var outer = $("<div>").css($.extend({
"left": "-1000px",
"overflow": "scroll",
"position": "absolute",
"top": "-1000px"
}, css)).append(inner).appendTo("body")
.scrollLeft(1000)
.scrollTop(1000);
var scrollSize = {
"height": (outer.offset().top - inner.offset().top) || 0,
"width": (outer.offset().left - inner.offset().left) || 0
};
outer.remove();
return scrollSize;
}
This jQuery-based solutions works in IE7+ and all other modern browsers (including mobile devices where scrollbar height/width will be 0).