console 命令行工具 X clear

console

function cell()
  {
  var x=document.getElementById('myTable').rows[0].cells;
  alert(x[0].innerHTML);
  }

<table id="myTable" border="1"> 
  <tbody>
   <tr> 
    <td>cell 1</td> 
    <td>cell 2</td> 
   </tr> 
   <tr> 
    <td>cell 3</td> 
    <td>cell 4</td> 
   </tr> 
  </tbody>
 </table> 
 <br> 
 <input type="button" onclick="cell()" value="显示第一个单元">