JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
        <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip
            ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril
            delenit augue duis dolore te feugait nulla facilisi.</p>
      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip
            ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril
            delenit augue duis dolore te feugait nulla facilisi.</p>
    </div>


    <canvas id="area" style=" width: 100%;height: 100%;position:fixed;top:0;left:0;"></canvas>

CSS

body {
    margin: 0px;
    padding:0px;
}

JavaScript

var canvas_down = false;  

var canvas = document.getElementById('area');
var ctx = canvas.getContext("2d");

//resize to be sure that pixels == width
window.addEventListener('resize', resizeCanvas, false);
function resizeCanvas() {
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;   
}
resizeCanvas();


ctx.fillStyle = "rgb(255,255,255)";
//ctx.fillRect(0, 0, $("#area").width(),$("#area").height()); 

canvas.addEventListener('mousedown', function (e) {
    canvas_down = true;    
}, false);

canvas.addEventListener('mouseup', function (e) {
    canvas_down = false;    
}, false);

canvas.addEventListener('mousemove', function (e) {
    if (canvas_down)
        eraser(e, 25);    
}, false);

   

function eraser(e, radius) {

    ctx.beginPath();
    var x2 = e.pageX - (radius/2);            
    var y2 = e.pageY- (radius/2);    
    ctx.fillRect(x2, y2, radius, radius);             
    ctx.closePath();

}