使用html5制作时钟
代码如下:
<!doctype html>
<html>
<head>
<title>html5时钟</title>
</head>
<body>
<canvas id = canvas></canvas></p> <p> <script>
var clock = function (canvas, options) {
this.canvas = canvas;
this.ctx = this.canvas.getcontext(2d);
this.options = options;
};</p> <p> clock.prototype = {
constructor: clock,
drawcircle: function () {
var ctx = this.ctx;
ctx.strokestyle = black;
ctx.arc(this.canvas.width / 2, this.canvas.height / 2, 50, 0, 2 * math.pi, false);
ctx.stroke();
},
drawnum: function () {
var ctx = this.ctx;
var angle = math.pi * 2 / 12;
for (var i = 1; i <= 12; i += 1) {
ctx.font = 20px georgia;
ctx.textalign = center;
ctx.textbaseline = 'middle';
ctx.filltext(string(i), this.canvas.width / 2 + math.cos(3 *math.pi / 2 + angle * i) * 40, this.canvas.height / 2 + math.sin(3 * math.pi / 2 + angle * i) * 40);
}
},
drawpointer: function () {
var ctx = this.ctx;
var that = this;
var date, hour, minute, second;
date = new date();
hour = date.gethours();
if (hour > 12) {
hour = hour % 12;
}
minute = date.getminutes();
second = date.getseconds();</p> <p> var b = minute * math.pi / 30;
var c = second * math.pi / 30;
var a = hour * math.pi / 6 + math.pi / 6 * minute / 60;
var minuteangle = math.pi * 2 / 3600;
var secondangle = math.pi * 2 / 60;
var hourangle = math.pi * 2 / 12 / 3600;</p> <p> ctx.beginpath();
ctx.save();
ctx.translate(that.canvas.width / 2, that.canvas.height / 2);
ctx.arc(0, 0, 3, 0, 2 * math.pi, false);
ctx.fill();
ctx.closepath();
ctx.beginpath();
a += hourangle;
ctx.rotate(a);
ctx.fillrect(-2, -22, 4, 30);
ctx.closepath();
ctx.beginpath();
b += minuteangle;
ctx.rotate(b - a);
ctx.fillrect(-1.5, -26, 3, 35);
ctx.closepath();
ctx.beginpath();
c += secondangle;
ctx.rotate(c - b);
ctx.fillrect(-1, -30, 2, 40);
ctx.closepath();
ctx.restore();
},
repaint: function () {
this.drawpointer();
this.drawcircle();
this.drawnum();
},
tik: function () {
var that = this;
var ctx = this.ctx;
this.repaint();
window.timer = setinterval(function () {
ctx.clearrect(0, 0, that.canvas.width, that.canvas.height);
that.repaint();
}, 1000);
}
};</p> <p> var options;
var clock = new clock(document.getelementbyid(canvas), options);
clock.tik();
</script>
</body>
</html>