Table checkboxes selection

To select or unselect checkboxes in a table I use the follow code

(function() {
    // checkboxes in the table
    var cbs = document.getElementsByName('checkboxes');
    // header checkbox
    var all = document.getElementById('header_checkbox');
    all.onclick = function() {
        for(var i=0;i<cbs.length;i++) {
            cbs[i].checked = this.checked;
        }
    }
    var cbClick = function() {
        all.checked = (function() {
            for(var i=0;i<cbs.length;i++) {
                if(cbs[i].checked != true) {
                    return false;
                }
            }
            return true;
        })();
    }
    for(var i=0;i<cbs.length;i++) {
        cbs[i].addEventListener('click', cbClick, true);
    }
})();