Question

I want to use javascript to set the attribute disabled=”disabled” to the with id age 2 when the checkbox with id “exactage” is enabled. Any ideas? Thanks in advance. A happy coder 🙂

 <select id="age">
        <option value="18"><18</option>
    </select>

    <select id="age2">
        <option value="18"><18</option>
    </select>

   <input type="checkbox" id="exactage"/> Require exact age

Answer 1

If by enabled you mean checked

if(document.getElementById('exactage').checked)
    document.getElementById('age2').setAttribute('disabled', 'disabled');

If by enabled you actually mean enabled, you can do this:

if(document.getElementById('exactage').getAttribute('disabled') !== null)
    document.getElementById('age2').setAttribute('disabled', 'disabled');