Set input text default value and select option value then disable

Question

Using JavaScript, how can I:

• set a default value (and disable it) on the textbox
• disable the <select> option "Days"

? This is my HTML:

Deliver every <input type="text" maxlength="2" size="3"> 
<select>
<option value="Days">Days</option>
<option value="Weeks">Weeks</option>
</select>

Answer 1

I hope this one would work.

<input type="text" id="defaultDays" size="3">
<select id="disableOption">
<option value="Days">Days</option>
<option value="Weeks">Weeks</option>
</select>

<script type="text/javascript"> 
  document.getElementById('defaultDays').setAttribute('value','28');
  document.getElementById('defaultDays').disabled = true;
  document.getElementById('disableOption').disabled = true;
</script>

Thank you guys for your previous comments.