var chess = document.getElementById('chess');
var context = chess.getContext('2d');

context.strokeStyle = '#BFBFBF';

var logo = new Image();
logo.src = "img/back.png";
logo.onload = function(){
 context.drawImage(logo,0,0,300,450);
 drawChessBoard();
}

var drawChessBoard = function() {
 for(var i = 0; i < 15; i++) {
  context.moveTo(15 + i * 30, 19);
  context.lineTo(15 + i * 30, 440);
  context.stroke();
  context.moveTo(15, 19 + i * 30);
  context.lineTo(286, 19 + i * 30);
  context.stroke();
 }
}