Calculation/app/view/template/preview_modal.ejs

<div class="modal fade" id="preview-calc-grid" data-backdrop="static">
    <div class="modal-dialog modal-lg" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title">预览</h5>
            </div>
            <div class="modal-body">
                <div style="height: 300px" id="preview-spread"></div>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-sm btn-secondary" data-dismiss="modal">关闭</button>
            </div>
        </div>
    </div>
</div>