html固定标题列、标题头table(4)

                </tr>
                <tr>
                  <td>13</td>
                  <td>13</td>
                </tr>
                <tr>
                  <td>14</td>
                  <td>14</td>
                </tr>
                <tr>
                  <td>15</td>
                  <td>15</td>
                </tr>
                <tr>
                  <td>16</td>
                  <td>16</td>
                </tr>
                <tr>
                  <td>17</td>
                  <td>17</td>
                </tr>
                <tr>
                  <td>18</td>
                  <td>18</td>
                </tr>
                <tr>