我的chessBoard的值有问题

var chessBoard=[];
for(var i=0;i<16;i++){
 chessBoard[i]=[];
 for(var j=0;j<16;j++){
  chessBoard[i][j]=0;
 }
}
var chess = document.getElementById('canvas1');
var context = chess.getContext('2d');
context.strokeStyle = '#eee';
var logo = new Image();
logo.src = './image/beijing.png';
logo.onload = function() {
    context.drawImage(logo, 0, 0, 405, 405);
    drawLine();
    oneStep(2, 2, true);
    oneStep(3, 3, false);
}

function oneStep(i, j, me) {
    context.beginPath();
    context.arc(15 + i * 25, 15 + j * 25, 10, 0, 2 * Math.PI);
    var gradient = context.createRadialGradient(15 + i * 25 + 2, 15 + j * 25 - 2, 6, 15 + i * 25 + 2, 15 + j * 25 - 2, 3);
    if (me) {
        gradient.addColorStop(0, '#0a0a0a');
        gradient.addColorStop(1, '#ccc');
    } else {
        gradient.addColorStop(0, '#ddd');
        gradient.addColorStop(1, '#fff');
    }

    context.fillStyle = gradient;
    context.closePath();
    context.fill();
}

/*这个函数用来画棋盘*/
function drawLine() {
    for (var i = 0; i < 16; i++) {
        context.moveTo(15 + 25 * i, 15);
        context.lineTo(15 + 25 * i, 390);
        context.moveTo(15, 15 + 25 * i);
        context.lineTo(390, 15 + 25 * i);
        context.stroke();
    }

}

chess.onclick=function(){
 console.log(chessBoard[i][j]);
}

二维数组打印的时候就会提示qizi.js:50 Uncaught TypeError: Cannot read property '16' of undefined不管这个数字设置多大都会出错，有遇到过同样问题的吗?顺便求解答