4 <canvas id=
"canvas" width=
"100" height=
"100"></canvas>
8 var canvas
= document
.getElementById('canvas');
9 var ctx
= canvas
.getContext('2d');
11 ctx
.fillStyle
= '#0f0';
12 ctx
.fillRect(0, 0, 100, 100);
15 ctx
.rect(30, 30, 40, 40);
19 ctx
.arc(50, 50, 25, 0, 2 * Math
.PI
);
22 ctx
.fillStyle
= '#f00';
24 ctx
.fillRect(0, 0, 100, 100);