JSFiddle - React, Tailwind, and code Playground

HTML

<select size="3">
    <option id="combostart" value="">First</option>
    <option>Blaa</option>
 </select>

<select id="combooptions" size="3">
    <option id="combostart" value="">First</option>
    <option>Blaa</option>
 </select>

<select id="combooptions2" size="3">
    <option id="combostart" value="">First</option>
    <option>Blaa</option>
 </select>

JavaScript

$("#combooptions")[0].length = 1;
$("#combooptions2 :not(:first-child)").remove();