<table id="tableInput">
  <thead>
  <tr>
    <th>Col 1</th>
    <th>Col 2</th>
  </tr>
  </thead>

  <tbody id='abc'>
  <tr>
    <td><input id="itemid" name="itemid"  type="text" size="20" /></td>
    <td>Col2 desc</td>
  </tr>
  <tr>
    <td><input id="itemid" name="itemid"  type="text" size="20" /></td>
    <td>Col2 desc</td>
  </tr>
  </tbody>
</table>

i=0;
while i < document.getElementById("tableInput").tBodies.length {
  x = document.getElementById("tableInput").tBodies[i].input.value);
  if x = "" {
      errorMsg = 1;
  }
 i++;
 }