Canvas贝塞尔三级曲线

两个控制点
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>bezierCurveTo</title>

</head>

<body>

    <canvas id='myCanvas' width='400' height='200'>

        your browser does not support canvas

    </canvas>

    <script type="text/javascript">

    var c = document.getElementById('myCanvas');

    var cxt = c.getContext('2d');

    cxt.beginPath();

    var sx = 20,

        sy = 100,

        cx1 = 45,

        cy1 = 70,

        cx2 = 95,

        cy2 = 130,

        ex = 120,

        ey = 100;

    cxt.moveTo(sx, sy);

    cxt.bezierCurveTo(cx1,cy1,cx2,cy2,ex,ey);

    cxt.moveTo(sx, sy);

    cxt.lineTo(cx1,cy1);

    cxt.lineTo(cx2,cy2);

    cxt.lineTo(ex,ey);

    cxt.moveTo(0, 100);

    cxt.lineTo(140, 100);

    cxt.stroke();

    </script>

</body>

</html>