Why can't I disable the input textbox in my table (I'm trying to use JavaScript only)?

Question

I'm trying to disable a few textboxes in a table using JavaScript.

My JavaScript

var table = {
  disableTextbox: function() {
    var rows = document.querySelectorAll('table tr');
    rows.forEach(function(row, index) {
    
    if (index === 1 || index === 7) {
      return;
    }

    var variable1 = row.cells[3];
    var variable2 = variable1.querySelector('input[type="text"]');
    
    if (variable2) {
      var variable3 = document.getElementsByTagName('td');
      variable3.disabled = true;
      }
    });
  }
};

table.disableTextbox();

<tr>
  <td>Employee Name:</td>
  <td>Schedule Time:</td>
  <td>Tasks Done:</td>
  <td><input type="text" name="yesOrNo" /></td>
</tr>

My HTML for one of the rows of the table. I didn't want to include all 10 lines because that's just a lot to put here and everything is the same except for text with the tags (for example, people's names that I didn't want to include on here)

All suggestions are appreciated! Thanks!

Answer 1

There's a couple of issues in your code.

Firstly getElementsByTagName() returns a NodeList, not a single element. Therefore you would need to loop through the list and set every Element within it to disabled, not the NodeList itself.

Secondly a td has no disabled property. That only applies to the input, so you're targetting the wrong element.

That being said, your code is a lot more complex than it needs to be. You can simplify it using querySelectorAll() and a combination of :not() and :nth-child() to leave the second and eighth rows enabled:

var table = {
  disableTextbox: function() {
    document.querySelectorAll('table tr:not(:nth-child(1)):not(:nth-child(7)) input')
      .forEach(el => el.disabled = true);
  }
};

table.disableTextbox();

<table>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
  <tr>
    <td>Employee Name:</td>
    <td>Schedule Time:</td>
    <td>Tasks Done:</td>
    <td><input type="text" name="yesOrNo" /></td>
  </tr>
</table>