JS Canvas Rainbow Waterfall Simulation SRC

<html>
<body onload="setInterval(drawe,312)" background-color="white">
<canvas id="myCanvas" width="1000" height="1000" style="background:black;">
</canvas>
<script>
var ii=555;
function drawe(){
ii++;
var text = "";
var possible = "FABCGDE0123456789";
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
for(var i=0; i!=6; i++)
text+=possible.charAt(Math.floor(Math.random()*possible.length));
ctx.strokeStyle='#'+text;
ctx.fillStyle="#"+text;
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var cts=c.getContext("2d");
ctx.beginPath();
ctx.fillRect(0,0,1000,Math.random()*ii,ii);
ctx.fill();
text='';
}
</script>
</body>