html5 canvas贝塞尔曲线篇(下)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>html5 canvas贝塞尔曲线篇</title>
<script src="js/modernizr.js"></script>
</head>
 
<body>
<h1>html5 canvas贝塞尔曲线篇</h1>
 
<script type="text/javascript">
window.addEventListener('load',eventWindowLoaded,false);
function eventWindowLoaded(){
    canvasApp();
}
function canvasSupport(){
    return Modernizr.canvas;
}
function canvasApp(){
    if(!canvasSupport()){
        return;
    }else{
        var theCanvas = document.getElementById('canvas')
        var context = theCanvas.getContext("2d")
 
    }
    drawScreen();
    function drawScreen(){
         context.beginPath();
         context.strokeStyle="red";
         context.lineWidth=2;
         context.moveTo(150,0); 
          
         context.bezierCurveTo(0,125,300,175,150,300); 
         context.stroke();
         context.closePath();
         //创建多弧点的贝塞尔曲线
          
         context.beginPath();
             context.strokeStyle="black";
                 context.lineWidth=2;
         context.moveTo(0,150);  //从0,150开始
          
         context.bezierCurveTo(150,0,175,300,300,150); 
         context.stroke();
         context.closePath();
    }
}
 
 
</script>
<canvas id="canvas" width="500" height="500">
你的浏览器无法使用canvas
你的支持是我最大的快乐！！
</canvas>
</body>
</html>