$("#ss").click(function (e) {
    //Acquire cell index from mouse-clicked point of regular cells which are neither fixed rows/columns nor row/column headers.
    var offset = $("#ss").offset();
    var x = e.pageX - offset.left;
    var y = e.pageY - offset.top;
    var target = activeSheet.hitTest(x, y);

    if (target &&
        (target.rowViewportIndex === 0 || target.rowViewportIndex === 1) &&
        (target.colViewportIndex === 0 || target.colViewportIndex === 1)) {
        alert("Row index of mouse-clicked cells: " + target.row + "\n" + "Column index of mouse-clicked cells: " + target.col);
    }
});