HTML代码

<!-- 弹窗 -->
<div class="modal fade" id="modal_20200114" tabindex="-1" role="dialog" aria-labelledby="ModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">公告</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">×</span>
        </button>
      </div>
      <div class="modal-body">
        内容
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-primary" data-dismiss="modal" id="modal_20200114_lock">我知道了，不要再弹出</button>
      </div>
    </div>
  </div>
</div>

JS代码（放到底部）

<script>
!function (){
    var a = $('#modal_20200114');
    var b = $('#modal_20200114_lock');
    var k = $.cookie('modal_20200114_lock');
    if(!k){
        a.modal('show');
        b.on('click', function() {
            $.cookie('modal_20200114_lock', '1');
        });
    }
}();
</script>