CalendarExtender控件被挡住

    <style type="text/css">
        .ajax__calendar_container
        {
            z-index: 1000;
            padding: 4px;
            position: absolute;
            cursor: default;
            width: 170px;
            font-size: 11px;
            text-align: center;
            font-family: tahoma,verdana,helvetica;
        }
        .ajax__calendar.ajax__calendar_container
        {
            z-index: 1000;
            border: 1px solid #646464;
            background-color: #ffffff;
            color: #000000;
        }
    </style>