HTML5 Canvas “红心一棵”
    效果图:

笛卡尔公式:r = a(1-sin弧度)画“红心”。
代码:
 <!DOCTYPE html>  
<html>  
<head>  
 <meta charset="gbk">  
 <title>HTML5 Canvas“红心一棵”</title>  
</head>  
<body>  
 <canvas id="canvas" width="600" height="300"></canvas>  
<script>  
   var canvas = document.getElementById("canvas");    
   var context = canvas.getContext('2d');    
   var width=canvas.width;  
   var height=canvas.height;  
   context.fillStyle="red";
   var  x,y,r;
     for(var i=0;i<=90;i++)
      {
         for(var j=0;j<=90;j++)
         {
            r=Math.PI/45*i*(1-Math.sin(Math.PI/45*j))*18;
            x=r*Math.cos(Math.PI/45*j)*Math.sin(Math.PI/45*i)+width/2;
            y=-r*Math.sin(Math.PI/45*j)+height/4;
            context.beginPath();
            context.arc(x,y,1,0,Math.PI*2);	
            context.fill();
         }	        
      }
  </script>
<body></html>
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http://www.108js.com/example.html