JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://amatiasq.com/fiddle-console.js"></script>
<table>
    <tr>
        <td>
            <canvas id="cnv1" width="128px" height="128px">
            </canvas>
        </td>
    </tr>
</table>

<input type=button onclick="Draw()"></input>

JavaScript

function Draw()
{
    alert("Test");
    var cnv = document.getElementById("cnv1");
    cnv.width = 0;
    cnv.width = 128;
    cnv.height = 128;
    var ctx = cnv.getContext("2d");
    ctx.fillStyle = "#ff0000";
    ctx.fillRect(0,0,128,128);
}