使用toDataURL()方法获取画布的图像数据URL。它将图形（画布）转换为64位编码的PNG URL。
您可以尝试运行以下代码将画布另存为图像-
<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<canvasid = "newCanvas" width = "450" height = "300"></canvas>
<script>
var canvas = document.getElementById('newCanvas');
var ctx = canvas.getContext('2d');
//画任何形状
ctx.beginPath();
ctx.moveTo(120, 50);
ctx.bezierCurveTo(130,100, 130, 250, 330, 150);
ctx.bezierCurveTo(350,180, 320, 180, 240, 150);
ctx.bezierCurveTo(320,150, 420, 120, 390, 100);
ctx.bezierCurveTo(130,40, 370, 30, 240, 50);
ctx.bezierCurveTo(220,7, 350, 20, 150, 50);
ctx.bezierCurveTo(250,5, 150, 20, 170, 80);
ctx.closePath();
ctx.lineWidth = 3;
ctx.fillStyle ='#F1F1F1';
ctx.fill();
ctx.stroke();
var dataURL =canvas.toDataURL();
</script>
</body>
</html>