                        课程
                    
                        /前端开发
                        
                            /Html5
                        
                        /Canvas 绘制时钟

为什么我做的多了一条线？不知到怎么清除，求大神帮忙！

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>canvas绘制时钟</title>
</head>
<body>
<canvas id="demo">
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</canvas>
<script>
(function () {
var canvas=document.getElementById("demo");
var ctx=canvas.getContext("2d");
canvas.height=600;
canvas.width=600;
var w=canvas.width;
var h=canvas.height;
var r=w/2;

function drawBackgroud() {
ctx.save();
ctx.translate(r,r);
ctx.lineWidth=15;
ctx.arc(0,0,r-15,0,2*Math.PI);
ctx.stroke();

var hoursNumber=[3,4,5,6,7,8,9,10,11,12,1,2];
for (var i=0;i<hoursNumber.length;i++)
{
ctx.font="35px Arial";
ctx.textAlign="center";
ctx.textBaseline="middle";
var rad=2*Math.PI/12*i;
var x=(r-60)*Math.cos(rad);
var y=(r-60)*Math.sin(rad);
ctx.fillText(hoursNumber[i],x,y);
}

for (var i=0;i<60;i++)
{
var rad=2*Math.PI/60*i;
var x=(r-35)*Math.cos(rad);
var y=(r-35)*Math.sin(rad);
ctx.beginPath();
if (i%5===0)
{
ctx.fillStyle="#000";
ctx.arc(x,y,5,0,2*Math.PI);
}
else
{
ctx.fillStyle="#ccc";
ctx.arc(x,y,5,0,2*Math.PI);
}
ctx.fill();
}
}

//绘制时针、分针、秒针
function drawDot() {
ctx.beginPath();
ctx.fillStyle="#fff";
ctx.arc(0,0,5,0,2*Math.PI);
ctx.fill();
}

function drawHour(hour,minute) {
ctx.save();
ctx.beginPath();
var rad=2*Math.PI/12*hour+2*Math.PI/12/60*minute;
ctx.rotate(rad);
ctx.lineWidth=10;
ctx.lineCap="round";
ctx.moveTo(0,20);
ctx.lineTo(0,-r/2);
ctx.stroke();
ctx.restore();
}
function drawMinute(minute) {
ctx.save();
ctx.beginPath();
var rad=2*Math.PI/60*minute;
ctx.rotate(rad);
ctx.lineWidth=5;
ctx.lineCap="round";
ctx.moveTo(0,20);
ctx.lineTo(0,-r+60);
ctx.stroke();
ctx.restore();
}
function drawSecond(second) {
ctx.save();
ctx.beginPath();
ctx.fillStyle="red";
var rad=2*Math.PI/60*second;
ctx.rotate(rad);
ctx.moveTo(2,20);
ctx.lineTo(-2,20);
ctx.lineTo(-1,-r+40);
ctx.lineTo(1,-r+40);
ctx.fill();
ctx.restore();
}
function draw() {
ctx.clearRect(0,0,w,h);
var now=new Date();
var hour=now.getHours();
var minute=now.getMinutes();
var second=now.getSeconds();
drawBackgroud();
drawHour(hour,minute);
drawMinute(minute);
drawSecond(second);
drawDot();
ctx.restore();
}
draw();
setInterval(draw,1000);
})();

</script>

</body>
</html>