JSFiddle - React, Tailwind, and code Playground

JavaScript

function init() {
    var body = document.getElementsByTagName("body")[0];
    var canvas = document.createElement("canvas");
    canvas.height = window.innerHeight;
    canvas.width = window.innerWidth;
    var context = canvas.getContext("2d");

    context.globalAlpha=0.3;

    for(var i=0;i<50;i++){
    	var colour = '#'+ Math.round(0xffffff * Math.random()).toString(16);
    	context.fillStyle = colour;
    	context.fillRect(Math.random()*window.innerWidth,Math.random()*window.innerHeight,Math.random()*80+20,Math.random()*80+20);
	}

    body.appendChild(canvas);
}
init();