JSFiddle - React, Tailwind, and code Playground
HTML
<select name="type_id" id="type_id">
<option value="1">Баннеры</option>
<option value="2">Шманеры</option>
</select>
<select name="size_id" id="size_id" multiple="multiple">
<option value="0">468x60</option>
<option value="1">240x400</option>
<option value="4">120x600</option>
<option value="5">300x250</option>
</select>
CSS
select option[disabled] {
display: none;
}
JavaScript
var type_id = document.getElementById("type_id");
type_id.onchange = function () {
if (type_id.options[type_id.selectedIndex].value == '2') {
var sel = document.getElementById('size_id');
sel.options[1].setAttribute('disabled', true);
sel.options[3].setAttribute('disabled', true);
}
};