function start() {
    toggle(0);
    toggle(1);
    toggle(2);
    toggle(3);
}
function toggle(index) {
    var selected = document.getElementById("chk" + index).checked;
    if (document.getElementById("ctl00_ContentPlaceHolder1_cell" + index)) {
        document.getElementById("ctl00_ContentPlaceHolder1_cell" + index).style.display = selected ? '' : 'none';
    }
}