Today Mission

반지름(r):
[JavaScript 소스]

<html>
    <head>
        <title> Today Mission </title>
        <script language="javascript">
var x1=0, x2=920, y1=0, y2=520;
function fun1()
{
    var c=document.getElementById("c1").getContext("2d");

    c.beginPath();
    c.strokeStyle="#4374D9";
    
    c.moveTo(x1,y2/2); c.lineTo(x2,y2/2);    
    c.moveTo(x2/2,y1); c.lineTo(x2/2,y2);
    c.stroke();
}
var r=0, cc=0;
var color=new Array("#4374D9","#47C83E","#8041D9", "#FF007F", "#BCE55C");
function fun2()
{
     var c=document.getElementById("c1").getContext("2d");
     var bx = document.getElementById("p1");
     
    c.beginPath();
    if(r%10==0) cc++;
    c.strokeStyle=color[cc%5];
 
     var x=-200, y;
     r +=1;
     bx.value = r;
     y = parseInt(Math.sqrt(r*r-x*x));
     c.moveTo(x+x2/2, y+y2/2);
     
     for(x=-199; x<=200; x+=1){
            y = parseInt(Math.sqrt(r*r-x*x));
            c.lineTo(x+x2/2,y+y2/2);
        }
     for(x=200; x>=-200; x-=1){
            y = parseInt(Math.sqrt(r*r-x*x));
            c.lineTo(x+x2/2,-1*y+y2/2);
        }

        c.stroke();
}
        </script>

    </head>
    <body>
        <h1> Today Mission </h1>
        반지름(r):<input type="text" size="10" id="p1" maxlength="30">
        <input type="button" value="go f1~" onClick="fun1()">
        <input type="button" value="go f2~" onClick="fun2()">
        <br>
        <canvas id="c1" width="900" height="500" style="border:1px solid#000000">
        </canvas>
    </body>
</html>