JSFiddle - React, Tailwind, and code Playground

HTML

<table border="0" cellspacing="0" cellpadding="3">
    <tbody>
        <tr>
            <td style="color:#e05627; font-size:12px; font-weight:bold">Length</td>
            <td>
                <input name="length" value="0" id="length" type="text"><span style="padding-left:5px;">Meter(s)</span>
            </td>
        </tr>
        <tr>
            <td style="color:#e05627; font-size:12px; font-weight:bold">Width</td>
            <td>
                <input name="width" value="0" id="width" type="text"><span style="padding-left:5px;">Meter(s)</span>
            </td>
        </tr>
        <tr>
            <td style="color:#e05627; font-size:12px; font-weight:bold">Tile Size</td>
            <td>
                <p>
                    <select name="size" id="size">
                        <option value="103">5.08 * 20.32 (2 * 8)</option>
                        <option value="125">6.25 * 20 (2.46 * 7.87)</option>
                        <option value="129">6.35 * 20.32 (2.5 * 8)</option>
                        <option value="210">8.25 * 25.4 (3.25* 10)</option>
                        <option value="400">20 * 20 (7.87 * 7.87)</option>
                        <option value="600">20 * 30 (7.87 * 11.81)</option>
                        <option value="619">20.32 * 30.48 (8 * 12)</option>
                        <option value="826">20.32 * 40.64 (8 * 16)</option>
                        <option value="900">30 * 30 (11.81 * 11.81)</option>
                        <option value="1600">40 * 40 (15.75 * 15.75)</option>
                        <option value="2025">45 * 45 (17.72 * 17.72)</option>
                        <option value="2500">50 * 50 (19.68 * 19.68)</option>
                        <option value="1032">25.4 * 40.64 (10 * 16)</option>
                        <option value="3600">60 * 60 (23.62 * 23.62)</option>
                        <option value="900">15 * 60 (5.9 * 23.62)</option>
                        <option value="899">29.99 * 29.99 (11.81 *...

JavaScript

$(document).ready (function caculateForm() {
    var length = document.getElementById('length').value;
    var width = document.getElementById('width').value;
    var size = document.getElementById('size').value;
    var compute = (length * width) / (size / 100);
    var total = compute * 100;
    var allowance = (compute * 100) * .10;
    allowance = Math.floor(total) + Math.floor(allowance + 1);
    document.getElementById('total').value = Math.floor(total);
    document.getElementById('allowance').value = allowance;
}});
                  

$(document).ready (function clearFileInput(id) {
    var elem = document.getElementById(id);
    elem.parentNode.innerHTML = elem.parentNode.innerHTML;
}});