Gets or sets the current vertical position of the Grid's scrollbar, when scrolling is on.

The vertical scroll position is the same as the number of pixels that are hidden from view above the scrollable area.

    dataSource: {
        data: gridData                 
    rowHover: false, 
    scrolling: {
        virtual: true
    sorting: true,
    height: 400

// set the current scroll to top

// prints 500