JSFiddle - React, Tailwind, and code Playground

HTML

<form action="" id="form">
    <select name="min">
        <option value="30">30</option>
        <option value="60">60</option>
        <option value="90">90</option>
        <option value="130">130</option>
        <option value="200">200</option>
    </select>
    <select name="max">
        <option value="30">30</option>
        <option value="60">60</option>
        <option value="90">90</option>
        <option value="130">130</option>
        <option value="200">200</option>
    </select>
    <button type="button" id="ok">ok</button>
</form>

JavaScript

document.querySelector('#ok').onclick = function(){
    var min = this.parentNode.querySelector('[name="min"]').value;
    var max = this.parentNode.querySelector('[name="max"]').value;
	alert(typeof min);
    alert(typeof max);
};