JSFiddle - React, Tailwind, and code Playground

HTML

<p>Lorem ipsum</p>

<div class="test"></div>

CSS

p {
    font-family: "Not existing", Verdana;
   font-size: 14px; 
}

JavaScript

/**
 * JavaScript code to detect available availability of a 
 * particular font in a browser using JavaScript and CSS. 
 * 
 * Author : Lalit Patel
 * Website: http://www.lalit.org/lab/jsoncookies
 * License: Creative Commons Attribution-ShareAlike 2.5
 *          http://creativecommons.org/licenses/by-sa/2.5/
 * Version: 0.15 
 *          changed comparision font to serif from sans-serif, 
 *          as in FF3.0 font of child element didn't fallback 
 *          to parent element if the font is missing.
 * Updated: 09 July 2009 10:52pm
 * 
 */

/**
 * Actual function that does all the work. Returns an array with all the info.
 * This test will fail for the font set as the default serif font.
 * 
 * Usage: d = new Detector();
 *        d.test('font_name');
 */
var Detector = function(){
    var h = document.getElementsByTagName("BODY")[0];
    var d = document.createElement("DIV");
    var s = document.createElement("SPAN");
    d.appendChild(s);
    d.style.fontFamily = "sans";            //font for the parent element DIV.
    s.style.fontFamily = "sans";            //serif font used as a comparator.
    s.style.fontSize   = "72px";            //we test using 72px font size, we may use any size. I guess larger the better.
    s.innerHTML        = "mmmmmmmmmmlil";        //we use m or w because these two characters take up the maximum width. And we use a L so that the same matching fonts can get separated
    h.appendChild(d);
    var defaultWidth   = s.offsetWidth;        //now we have the defaultWidth
    var defaultHeight  = s.offsetHeight;    //and the defaultHeight, we compare other fonts with these.
    h.removeChild(d);
    /* test
     * params:
     * font - name of the font you wish to detect
     * return: 
     * f[0] - Input font name.
     * f[1] - Computed width.
     * f[2] - Computed height.
     * f[3] - Detected? (true/false).
     */
    function debug(font) {
        h.appendChild(d);
        var f = [];
        f[0] = s.style.fontFamily =...