The Memory (aka Concentration) Game - The Essential Guide to HTML5 - page 161

for (i=1;i<this.n;i++) { For loop for the

successive points

ctx.lineTo(this.sx+rad*Math.cos((i-
.5)*this.angle),this.sy+rad*Math.sin((i-.5)*this.angle));

Set up drawing of line
segments

} Close for loop

ctx.fill();

Fill in the path

}

Close function

function drawback() {

Function header

ctx.fillStyle = backcolor; Set card back color

ctx.fillRect(this.sx,this.sy,this.swidth,this.sheight);

Draw rectangle

}

Close function

function choose(ev) { Function header for

choose (click on a
card)

var mx; Variable to hold

mouse x

var my;

Variable to hold
mouse y

var pick1; Variable to hold

reference to created
Polygon object

var pick2;

Variable to hold
reference to created
Polygon object

if ( ev.layerX || ev.layerX == 0) { Can we use layerX

and layerY ?

mx= ev.layerX; Set mx

Set my

my = ev.layerY;