Ive been learning javascript and i cant get it to draw a half circle.

here is the code i came up with

<HTML>

<HEAD>

<TITLE>

Divisions in jscript

</TITLE>

<script language = "javascript">

var mx; //users x value

var my; //users y value

var mr; //users radius

var sy; //solve for y

var i; //for loops

var a; //misc. var

var b; //misc. var

var c; //misc. var

var d; //misc. var

sy = 1;

mx = 100;

my = 100;

mr = 30;

//draw a half circle using the equation y = sqrt(r^2-(x-j)^2-k^2); where (j, k) is the center of the circle

for (i = 100; i < 131; i = i + 1)

{

a = Math.pow(mr, 2);

b = i - mx;

c = Math.pow(b, 2);

sy = a - c;

sy = Math.floor(Math.sqrt(sy) + my);

document.write("<div id = m["+i+"] STYLE = 'POSITION: ABSOLUTE; TOP: "+sy+"; LEFT: "+i+";'><img src = 'reddot.jpg'></DIV>");

// document.write("a is "+a+"... b is "+b+"... c is "+c+"... d is "+d+"... sy is "+sy+"<BR>"); //this line may be used to see the value of each variable dependant on the loop

}

</script>

</HEAD>

<BODY>

</BODY>

</HTML>

does anyone see the problem???