你的逻辑有点问题。我将在下面解释我的。

function drawCheckeredBackground(can, nRow, nCol) {
    var ctx = can.getContext("2d");
    var w = can.width;
    var h = can.height;
    nRow = nRow || 8;    // default number of rows
    nCol = nCol || 8;    // default number of columns
    w /= nCol;            // width of a block
    h /= nRow;            // height of a block
    for (var i = 0; i < nRow; ++i) {
        for (var j = 0, col = nCol / 2; j < col; ++j) {
            ctx.rect(2 * j * w + (i % 2 ? 0 : w), i * h, w, h);
        }
    }
    ctx.fill();
}
var canvas = document.getElementById("canvas");
drawCheckeredBackground(canvas);

<canvas id="canvas" width="300" height="300"></canvas>

嵌套的for循环在一行中绘制块。

2 * j * w + (i % 2 ? 0 : w)是每隔一行移动每个块的 x 坐标。

循环通过行和列像这样：

for (let column = 0; column < board.columns; column++) {
  for (let row = 0; row < board.rows; row++) {
  }
}

如果以下任一条件为真，则通过绘制矩形来创建方格图案：

行是偶数，列是奇数

行是奇数，列是偶数

在代码中：

if (row % 2 === 0 && column % 2 === 1 || row % 2 === 1 && column % 2 === 0) {
  canvas.context.rect(
    column * column_width,
    row * row_height,
    column_width,
    row_height
  );
}

const canvas = {
  element: document.querySelector("canvas"),
  context: document.querySelector("canvas").getContext('2d')
}
const board = {
  rows: 15,
  columns: 17,
  colors: {
    light: '#a3cf53',
    dark: '#abd55a'
  }
}
canvas.context.beginPath();
canvas.context.fillStyle = board.colors.dark;
canvas.context.rect(0, 0, canvas.element.width, canvas.element.height);
canvas.context.fill();
canvas.context.beginPath();
canvas.context.fillStyle = board.colors.light;
for (let column = 0; column < board.columns; column++) {
  for (let row = 0; row < board.rows; row++) {
    if (row % 2 === 0 && column % 2 === 1 || row % 2 === 1 && column % 2 === 0) {
      canvas.context.rect(
        column * canvas.element.width / board.columns,
        row * canvas.element.height / board.rows,
        canvas.element.width / board.columns,
        canvas.element.height / board.rows
      );
    }
  }
}
canvas.context.fill();

body {
  margin: 0;
}

<canvas width="595" height="525"></canvas>

为了改变正方形的颜色，我们可以使用以下事实：（1,1），（2,2），（3,3），...处的对角正方形将具有相同的颜色，例如白色，而（1,2），（2,3），（3,4），...将具有相同的颜色，例如黑色。我们在这里注意到一个模式，即在(col, row)中，如果1

代码逻辑：

if ((i % 2 == 0 && j % 2 == 0) || (i % 2 != 0 && j % 2 != 0)){
    square is white/color1
}
else{
    square is black/color2
}                   
     

const board = document.getElementById("board")
const ctx = board.getContext("2d")
let cols = 8 
let rows = 8
let squareSize = 50
function drawCheckeredBoard(ctx, squareSize, rows, cols) {
    let whiteSquareColor = "#ffe6cc"
    let blackSquareColor = "#cc6600"
    for (let j = 0; j < rows; j++)
        for (let i = 0; i < cols; i++) {
            if ((i % 2 == 0 && j % 2 == 0) || (i % 2 != 0 && j % 2 != 0)) 
                ctx.fillStyle = whiteSquareColor
            else ctx.fillStyle = blackSquareColor
            ctx.fillRect(i * squareSize, j * squareSize, squareSize, squareSize)
        }
}
drawCheckeredBoard(ctx, squareSize, rows, cols)

<canvas id="board" width="400" height="400">