循环中document.getElementById的结果保持不变

Question

<?php for($i=0; $i< mysqli_num_rows($result); $i++){  ?>

<table id="t01" style="width:100%">
<tr>
<th colspan="2"><?php print_r($results[$i]['arr_question']); ?></th>
  </tr>
  <tr>
    <td><?php print_r($results[$i]['a']); ?></td>
    <td><?php print_r($results[$i]['b']); ?></td>
  </tr>
  <tr>
    <td><?php print_r($results[$i]['c']); ?></td>
    <td><?php print_r($results[$i]['d']); ?></td>
  </tr>
  <tr> 
  <td colspan="2"><button type="button" onClick="document.getElementById('').innerHTML= '<?php print_r($results[$i]['answer']); ?>'"> Answer </button>
  <p id=''></p>
  </td>
  </tr>
  <tr> <td colspan="2"><?php print_r($results[$i]['description']); ?></td>
  </tr>
</table>
</br>
<?php } ?>

In this code document.getElementById('').innerHTML is not working properly, it returns the same value while clicking on button in loop, when i put id equals $i it return the value in same place at every loop, it overrides the data at same place, when i put any static value it returns same. What should i do for getting the different value at different places. Any help will be appreciable.

Answer 1

You cannot have empty ids, assign an id as follows:

 <p id='p-<?php echo $i; ?>'></p>

And use it as follows in the query selector:

<button type="button" onClick="document.getElementById('p-<?php echo $i; ?>').innerHTML= '<?php print_r($results[$i]['answer']); ?>'"> Answer </button>