                        课程
                    
                        /前端开发
                        
                            /Html5
                        
                        /炫丽的倒计时效果Canvas绘图与动画基础

为啥显示不出来求大神帮看看

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" type="text/css" href="reset.css">
</head>
<body>
    <canvas id="canvas" style="border: 1px solid #aaa;display: block;margin:50px auto">

    </canvas>
    <script type="text/javascript">
 var tangram =[
            {p:[{x:0,y:0},{x:800,y:0},{x:400,y:400}],color:"#caff67"},
 {p:[{x:0,y:0},{x:400,y:400},{x:0,y:800}],color:"#67becf"},
 {p:[{x:800,y:0},{x:800,y:400},{x:600,y:600},{x:600,y:200}],color:"#ef3d61"},
 {p:[{x:600,y:200},{x:600,y:600},{x:400,y:400}],color:"#f9f51a"},
 {p:[{x:400,y:400},{x:600,y:600},{x:400,y:800},{x:200,y:600}],color:"#a594c0"},
 {p:[{x:200,y:60},{x:400,y:800},{x:0,y:800}],color:"#fa8ecc"},
 {p:[{x:800,y:0},{x:400,y:800},{x:400,y:800}],color:"#f6ca29"},
 ];
 window.onload = function () {
            var canvas = document.getElementById("canvas");
 var context = canvas.getContext("2d");
 canvas.width = 800;
 canvas.height = 800;


 for (var i = 0; i < tangram.length; i++) {
                draw(tangram[i], context);
 }
        }
        function draw(piece,cxt) {
            cxt.beginPath();
 cxt.moveTo(piece.p[0].x,piece.p[0].y);
 for( var i = 1 ;i<piece.length;i++){
                cxt.lineTo( piece.p[i].x,piece.p[i].y);
 }
            cxt.closePath();

 cxt.fillStyle = piece.color;

 cxt.fill();


 }

    </script>
</body>
</html>