Canvas - Drawing with Lines

HTML5 canvas demo

HTML

<canvas id="myCanvas" width="400" height="600" />

JavaScript

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

ctx.strokeStyle = 'rgba(0, 0, 0, 0.5)';
ctx.lineWidth = 10;
ctx.beginPath();
ctx.moveTo(150, 20);
ctx.lineTo(75, 200);
ctx.lineTo(225, 200);
ctx.lineTo(150, 20);
ctx.strokeBehind = true;
//ctx.lineJoin='square';  //miter
/* ctx.miterLimit = 1; */
//ctx.lineCap = 'round'; //butt
ctx.closePath();
ctx.stroke();    
ctx.fillStyle = 'yellow';
ctx.fill();