%%javascript

function doit() {
    var parent = element;
    while (parent.length && !parent.hasClass('cell')) {
        parent = parent.parent();
    }
    if (parent.length === 0) {
        // try again later
        setTimeout(doit, 100);
        return;
    }
    var cell_elements = Jupyter.notebook.get_cell_elements();
    var cell_idx = cell_elements.index(parent);
    var cell = Jupyter.notebook.get_cell(cell_idx);
    element.append($("<b>").text("Cell index " + cell_idx))
}
doit();