适逢国庆佳节，用代码画国旗试试
<html>
<head>
<script>
var col=new Array("red","brown");
var ticker=0;
var step=0;
function drawBackground(){
var g=document.getElementById("background").getContext("2d");
var grd=g.createLinearGradient(-560+ticker, 0, 1400+ticker,0);
for (var i=0; i<10; i++)
grd.addColorStop(i/10,col[(i + step)%col.length]);
ticker=ticker+10;
if (ticker>=196){
ticker=0;
step++;
}
g.fillStyle=grd;
g.fillRect(0,0,1600,700);
}
function preperation(){
setInterval('drawBackground()',100);
}
</script>
<style type="text/css">
#myCanvas{
z-index:2;
position:absolute; left:0px; top:-5px;
}
#background{
z-index:1;
position:absolute;
left:0px;
top:0px;
}
</style>
</head>
<body onLoad="preperation()">
<canvas id="myCanvas" width="900" height="600" >
Your browser does not support the HTML5 canvas tag.
</canvas>
<canvas id="background" width="1600" height="700" ></canvas>
<script>
var x=new Array(0,12,54,18,28,0,-28,-18,-54,-12,0); //五角星样品坐标xx数组
var y=new Array(-53,-17,-17,1,45,19,45,1,-17,-17,-53); //五角星样品坐标y数组
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d"); //获得画笔
//样品数组x轴坐标 a , 和y轴坐标 b
//指定位置[locationX,locationY]
//真实五角星的大小，与样品五角星尺寸之比 f
//五角星画完后，旋转的角度 rotation
function star(a,b,locationX,locationY,f,rotation){
ctx.save();//记录画图（画笔）的初始环境
ctx.translate(locationX,locationY);
ctx.rotate(rotation*Math.PI/180.0);
ctx.beginPath();
ctx.moveTo(Math.round(a[0]*f),Math.round(b[0]*f));
for (var i=1;i<a.length;i++)
ctx.lineTo(Math.round(a[i]*f),Math.round(b[i]*f));
ctx.closePath();
ctx.fillStyle="yellow";
ctx.fill();
ctx.restore();//还原画图（画笔）的初始环境
}
star(x,y,165,165,1.4,0);//画大五角星
star(x,y,301,65,0.5,30);//画小五角星
star(x,y,362,126,0.5,-30);//画小五角星
star(x,y,359,216,0.5,0);//画小五角星
star(x,y,301,273,0.5,30);//画小五角星
</script>
</body>
</html>
python版本实现
#coding=utf-8
'''
Created on 2014-11-17
@author: Neo
'''
import turtle
import math
def draw_polygon(aTurtle, size=50, n=3):
''' 绘制正多边形
args:
aTurtle: turtle对象实例
size: int类型，正多边形的边长
n: int类型，是几边形
'''
for i in xrange(n):
aTurtle.forward(size)
aTurtle.left(360.0/n)
def draw_n_angle(aTurtle, size=50, num=5, color=None):
''' 绘制正n角形，默认为黄色
args:
aTurtle: turtle对象实例
size: int类型，正多角形的边长
n: int类型，是几角形
color: str， 图形颜色，默认不填色
'''
if color:
aTurtle.begin_fill()
aTurtle.fillcolor(color)
for i in xrange(num):
aTurtle.forward(size)
aTurtle.left(360.0/num)
aTurtle.forward(size)
aTurtle.right(2*360.0/num)
if color:
aTurtle.end_fill()
def draw_5_angle(aTurtle=None, start_pos=(0,0), end_pos=(0,10), radius=100, color=None):
''' 根据起始位置、结束位置和外接圆半径画五角星
args:
aTurtle: turtle对象实例
start_pos: int的二元tuple，要画的五角星的外接圆圆心
end_pos: int的二元tuple，圆心指向的位置坐标点
radius: 五角星外接圆半径
color: str， 图形颜色，默认不填色
'''
aTurtle = aTurtle or turtle.Turtle()
size = radius * math.sin(math.pi/5)/math.sin(math.pi*2/5)
aTurtle.left(math.degrees(math.atan2(end_pos[1]-start_pos[1], end_pos[0]-start_pos[0])))
aTurtle.penup()
aTurtle.goto(start_pos)
aTurtle.fd(radius)
aTurtle.pendown()
aTurtle.right(math.degrees(math.pi*9/10))
draw_n_angle(aTurtle, size, 5, color)
def draw_5_star_flag(times=20.0):
''' 绘制五星红旗
args:
times: 五星红旗的规格为30*20， times为倍数，默认大小为10倍， 即300*200
'''
width, height = 30*times, 20*times
# 初始化屏幕和海龟
window = turtle.Screen()
aTurtle = turtle.Turtle()
aTurtle.hideturtle()
aTurtle.speed(10)
# 画红旗
aTurtle.penup()
aTurtle.goto(-width/2, height/2)
aTurtle.pendown()
aTurtle.begin_fill()
aTurtle.fillcolor('red')
aTurtle.fd(width)
aTurtle.right(90)
aTurtle.fd(height)
aTurtle.right(90)
aTurtle.fd(width)
aTurtle.right(90)
aTurtle.fd(height)
aTurtle.right(90)
aTurtle.end_fill()
# 画大星星
draw_5_angle(aTurtle, start_pos=(-10*times, 5*times), end_pos=(-10*times, 8*times), radius=3*times, color='yellow')
# 画四个小星星
stars_start_pos = [(-5, 8), (-3, 6), (-3, 3), (-5, 1)]
for pos in stars_start_pos:
draw_5_angle(aTurtle, start_pos=(pos[0]*times, pos[1]*times), end_pos=(-10*times, 5*times), radius=1*times, color='yellow')
# 点击关闭窗口
window.exitonclick()
if __name__ == '__main__':
draw_5_star_flag()
除了javascript,python版本，还有java，c++,ruby等版本
详见:国庆节，我们用代码来画个国旗
