画一个扁圆 _Web前端

画一个椭圆
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>test</title>
<script type="text/javascript">
    /*
* Draw a Oval
* author : 李英夫, Thanks for 袁洲's help in math.
* The following is the formula of Oval.
* All dots is drawn by it.
* x = r*a*cosθ　(0 <= θ <= 2π)
* y = r*b*sinθ　(0 <= θ <= 2π)
* b*b + r*r = a*a //Pythagoras Theorem
*/
    var Circle = {
        centre_of_circle : {x:200,y:200},
     radius : 12,
   dot : function(x,y,w){
    return "<div id='dot_"+x+y+"' style='display:none;font-size:0;width:"+w+"px;height:"+w+"px;position:absolute;background-color:#000;top:"+(y)+"px;left:"+(x)+"px'></div>";
   },
   draw : function(){
    var s = "",
     dots = 500,
     a = 15,
     b = 9,
     dotsArr = [];
    for(var i = 0; i < dots; i++){
       var x = Circle.centre_of_circle.x+Circle.radius*Math.cos(i*2*Math.PI/dots)*a;
     var y = Circle.centre_of_circle.y+Circle.radius*Math.sin(i*2*Math.PI/dots)*b;
                s += Circle.dot(x, y, 2);
     dotsArr.push({"y":y,"x":x});
    }
    document.body.innerHTML = s;
    return dotsArr;
   }
    }
    window.onload = function(){
        var dots = Circle.draw();
   var count = 0;
   var t = window.setInterval(function(){
     document.getElementById("dot_"+dots[count].x+dots[count].y).style.display = "block";
     count++;
     if(count >= dots.length) window.clearInterval(t);
   },1);
    }
</script>
</head>

<body>
</body>
</html>