jsp代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<canvas id="drawing"></canvas>
<script>
var drawing = document.getElementById('drawing');
if(drawing.getContext){
var cxt = drawing.getContext('2d');
var W = drawing.width = 200;
var H = drawing.height = 200;
var R = W / 2;
var cw = cxt.lineWidth = 0.1*R;
function drawStatics(){
cxt.save();
cxt.translate(R,R);
cxt.beginPath();
cxt.lineWidth = 0.1*R;
cxt.arc(0,0,R-cw/2,0,2*Math.PI,false);
cxt.stroke();
cxt.beginPath();
cxt.font = 0.2 * R + 'px 宋体';
cxt.textAlign = 'center';
cxt.textBaseline = 'middle';
var r1 = 0.8*R - cw/2;
for(var i = 12; i > 0; i--){
var radius = 2*Math.PI/12 * i + 1.5*Math.PI;
var x = Math.cos(radius) * r1;
var y = Math.sin(radius) * r1;
cxt.fillText(i,x,y);
}
cxt.beginPath();
var r2 = 0.9*R - cw/2;
for(var i = 0; i < 60; i++){
var radius = 2*Math.PI/60*i + 1.5*Math.PI;
var x = Math.cos(radius) * r2;
var y = Math.sin(radius) * r2;
cxt.beginPath();
if(i%5 === 0){
cxt.arc(x,y,cw/5,0,2*Math.PI,false);
}else{
cxt.arc(x,y,cw/8,0,2*Math.PI,false);
}
cxt.fill();
}
cxt.restore();
}
function drawDot(){
cxt.save();
cxt.translate(R,R);
cxt.beginPath();
cxt.arc(0,0,cw/3,0,2*Math.PI,false);
cxt.fillStyle = '#fff';
cxt.fill();
cxt.restore();
}
function drawSecond(second){
cxt.save();
cxt.translate(R,R);
cxt.beginPath();
var radius = 2*Math.PI/60 * second;
cxt.rotate(radius);
cxt.lineWidth = 2;
cxt.moveTo(0,cw*2);
cxt.lineTo(0,-0.8*R);
cxt.strokeStyle = 'red';
cxt.stroke();
cxt.restore();
}
function drawMinute(minute,second){
cxt.save();
cxt.translate(R,R);
cxt.beginPath();
var radius = 2*Math.PI/60 * minute;
var sRaiuds = 2*Math.PI/60/60 * second;
cxt.rotate(radius + sRaiuds);
cxt.lineWidth = 4;
cxt.lineCap = 'round';
cxt.moveTo(0,cw);
cxt.lineTo(0,-(0.8*R - cw/2));
cxt.stroke();
cxt.restore();
}
function drawHour(hour,minute){
cxt.save();
cxt.translate(R,R);
cxt.beginPath();
var radius = 2*Math.PI/12 * hour;
var mRaiuds = 2*Math.PI/12/60 * minute;
cxt.rotate(radius + mRaiuds);
cxt.lineWidth = 6;
cxt.lineCap = 'round';
cxt.moveTo(0,cw/2);
cxt.lineTo(0,-(0.8*R - cw*2));
cxt.stroke();
cxt.restore();
}
function draw(){
cxt.clearRect(0,0,W,H);
drawStatics();
var now = new Date();
drawHour(now.getHours(),now.getMinutes());
drawMinute(now.getMinutes(),now.getSeconds());
drawSecond(now.getSeconds());
drawDot();
}
draw();
设置函数循环运行时间单位 （ms）
setInterval(draw,500);
}
</script>
</body>
</html>