JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
<body id="main">
<canvas id="myCanvas" width="500" height="150"></canvas>
</body>
</html>

JavaScript

var c = document.getElementById("myCanvas");
    var ctx = c.getContext("2d");
    ctx.font = "10px Arial";
    var txt = "Hello World";
    window.alert (ctx.measureText(txt).width);