`<canvas width="600" height="400"></canvas>
<script>
var tela = document.querySelector("canvas");
var pincel = tela.getContext("2d");
pincel.fillStyle = "grey";
pincel.fillRect(0, 0, 600, 400);
pincel.fillStyle = "blue";
function cliquei(evento) {
var x = evento.pageX - tela.offsetLeft;
var y = evento.pageY - tela.offsetTop;
pincel.beginPath();
pincel.arc(x, y, 10, 0, 2 * 3.14);
pincel.fill();
}
tela.onclick = cliquei;
var aux = 0;
function mudaCor() {
var cores = ["green", "red", "white", "magenta", "black", "blue"];
pincel.fillStyle = cores[aux];
aux = aux + 1;
if (aux == cores.length) {
aux = 0;
}
return false;
}
tela.oncontextmenu = mudaCor;
</script>
