效果图：
提示：把代码复制到一个html文件中并保存，直接打开即可看到效果。
实现代码：
<!doctype html>
<html>
<head>
<meta charset = "gbk">
<title>html5 demo</title>
<style type="text/css">
#apdiv1 {
position:absolute;
width:120px;
height:300px;
z-index:1;
left: 840px;
top: 80px;
}
</style>
</head>
<body>
<canvas id="canvas" width="800" height="600" style="border:1px solid #c3c3c3;">
your browser does not support the canvas element. </canvas>
<div id="apdiv1">
<form>
玫瑰曲线方程：<br>
r=a+bsin(m/n*x)<br><br>
选择参数：<br><br>
m: <input type="number" name="m" min="2" max="29" value="29"/><br><br>
n: <input type="number" name="n" min="1" max="12" value="11"/><br><br>
a: <input type="number" name="a" min="0" max="5" value="1"/><br><br>
b: <input type="number" name="b" min="1" max="7" value="5"/><br><br>
<input type="button" value=" 画 图 " onclick="draw();"><br><br>
<hr><br>
<input type="button" value=" 画 图 2 " onclick="draw2();"><br><br>
<hr><br>
<input type="button" value=" 心形图 " onclick="draw3();"><br>
</form>
</div>
<script type="text/javascript">
function draw() {
var ctx = document.getelementbyid('canvas').getcontext('2d');
ctx.save();
ctx.translate(400,300);
ctx.clearrect(-400,-300,800,600);
ctx.strokestyle = "#cc0000";
var a = 0, b = 1, m = 6, n = 1;
m = document.forms[0].m.value;
n = document.forms[0].n.value;
a = document.forms[0].a.value;
b = document.forms[0].b.value;
drawrose(ctx,a,b,m,n);
ctx.restore();
}
function drawrose(ctx,a,b,m,n){
ctx.beginpath();
var e = 0, c = 120;
var k = 2 * math.pi / 360;
do {
var r = a/b + math.sin( m * e / n * k);
r = r * c;
var x = r * math.cos( e * k );
var y = r * math.sin( e * k );
e += 0.1;
ctx.lineto(x,y);
} while ( e <= 4320 );
ctx.stroke();
}
function draw2(){
var ctx = document.getelementbyid('canvas').getcontext('2d');
ctx.save();
ctx.translate(400,300);
ctx.clearrect(-400,-300,800,600);
ctx.strokestyle = "#cc0000";
ctx.beginpath(); //ctx.moveto(0,0);
var e = 0, c = 150;
var k = 2 * math.pi / 360;
do {
x = 150*math.cos( 5/2 * e*k ) + 50*math.cos( 15/16 * 5/2 * e*k );
y = 150*math.sin( 5/2 * e*k ) - 50*math.sin( 15/16 * 5/2 * e*k );
e += 0.1;
ctx.lineto(x,y);
} while ( e <= 3600 );
ctx.stroke();
ctx.restore();
}
function draw3(){
var ctx = document.getelementbyid('canvas').getcontext('2d');
ctx.save();
ctx.translate(400,300);
ctx.clearrect(-400,-300,800,600);
ctx.strokestyle = "#ff0000";
ctx.beginpath();
var x = 1, y;
do {
y = -80*(math.sqrt(1-x*x) + math.pow(x*x,1/3));
x -= 0.001;
ctx.lineto(100*x,y);
} while ( x >= -1 );
do {
y = 80*(math.sqrt(1-x*x) - math.pow(x*x,1/3));
x += 0.001;
ctx.lineto(100*x,y);
} while ( x <= 1 );
ctx.closepath();
var grad = ctx.createradialgradient(-40,-60,10,-40,-40,200);
grad.addcolorstop(0, "#ffcc00");
grad.addcolorstop(1, "#ff0000");
ctx.fillstyle = grad;
ctx.fill();
// ctx.stroke();
ctx.restore();
}
window.onload = function (){
draw();
}
</script>
</body>
</html>
