重新加载EasyUI datagrid内容

Question

我正在制作一个简单的easyui网格，如下所示：

<div id="tb" style="padding:3px">
    <input type="button" value="change content" id="update_data" />
</div>
<table id="tt"  class="easyui-datagrid" style="width:600px;height:250px"

           title="Load Data" iconCls="icon-save"
           rownumbers="true" pagination="true">
        <thead>
            <tr>
                <th field="itemid" width="80">Item ID</th>
                <th field="productid" width="80">Product ID</th>
                <th field="listprice" width="80" align="right">List Price</th>
                <th field="unitcost" width="80" align="right">Unit Cost</th>
                <th field="attr1" width="150">Attribute</th>
                <th field="status" width="60" align="center">Stauts</th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 2</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>
            <tr>
                <td>Data 1</td>
                <td>Data 2</td>
                <td>Data 3</td>
                <td>Data 4</td>
                <td>Data 5</td>
                <td>Data 6</td>
            </tr>

        </tbody>
    </table>

要求是替换网格内容，所以我编写了以下代码

<script>
    $(document).ready(function(){
    $('#update_data').on('click', function () {

        $('#update_data').attr("value", "rrr");

        var content = '';

        for (var i = 0; i < 50; i++) {
            content += '<tr>';

            content += '<td>' + i + '</td>';
            content += '<td>' + i + '</td>';
            content += '<td>' + i + '</td>';
            content += '<td>' + i + '</td>';
            content += '<td>' + i + '</td>';
            content += '<td>' + i + '</td>';
            content += '</tr>';
        }

        $('#tt tbody').html(content);

      $('#tt').datagrid('reload');

    });
    });
</script>

代码不起作用。调试时，我删除了“ easyui-datagrid”类，并且html表更改了内容，没有问题

以原始值正确显示了网格，但是当按下按钮时没有任何变化