function addEvent(obj, evType, fn, useCapture) {
    if (obj.addEventListener) {
        obj.addEventListener(evType, fn, useCapture);
        return true;
    } else if (obj.attachEvent) {
        var r = obj.attachEvent('on' + evType, fn);
        return r;
    } else {
        obj['on' + evType] = fn;
    }
}