JSFiddle - React, Tailwind, and code Playground

HTML

<form name="myform" method="get" action="">
    <select id="s" onchange="createtext()" size="3" name="s">
        <option>
          Visa Card
        </option><option>
          Mastercard
        </option><option>
          American Express
        </option>
    </select>
</form>

JavaScript

function createtext()
{
    var myform = document.getElementById('myform');
    var var1 = document.getElementById('s');
    var var2=var1.value;    
    
    if (var2 == "American Express")
    {
        var selector = document.createElement('select');
        selector.id = 'gift';
        selector.name = 'gift';
        selector.size = '2';
        myform.appendChild(selector);
        
        var option = document.createElement('option');
        option.value = '0';
        option.appendChild(document.createTextNode('Gift card'));
        selector.appendChild(option);
        
        option = document.createElement('option');
        option.value = '1';
        option.appendChild(document.createTextNode('Fully owned card'));
        selector.appendChild(option);
    
    }
    else
    {
        myform.removeChild(gift);    
    }
}