// function for scrollbar click detection
var clickedOnScrollbar = function(mouseX){
  if( $(window).outerWidth() <= mouseX ){
    return true;
  }
}

// detect click for mousedown event
$(document).mouseup(function(e){
  if( clickedOnScrollbar(e.clientX) ){
    alert("clicked on scrollbar");
  }
});

var clickedOnScrollbar = function(mouseX){
  if (window.outerWidth() <= mouseX) {
    return true;
  }
};

document.addEventListener('mouseup', function(e) {
  if (clickedOnScrollbar(e.clientX)) {
    alert('clicked on scrollbar');
  }
});

        var clickedOnScrollbar = function(mouseX){
            if (document.body.clientWidth <= mouseX) {
                return true;
            }
 
        };

        document.addEventListener('mouseup', function(e) {
            if (clickedOnScrollbar(e.clientX)) {
                alert('clicked on scrollbar');
            }
        });

if (document.body.offsetWidth <= mouseX) {