希望添加具有画布元素的背景

<canvas id="myCanvas" width="800" height="600"></canvas>

var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");

// 绘制背景颜色
ctx.fillStyle = "blue";
ctx.fillRect(0, 0, canvas.width, canvas.height);

// 绘制背景图案
var img = new Image();
img.src = "background.jpg";
img.onload = function() {
  ctx.drawImage(img, 0, 0);
};

// 绘制背景形状
ctx.beginPath();
ctx.arc(canvas.width/2, canvas.height/2, 100, 0, 2*Math.PI);
ctx.fillStyle = "red";
ctx.fill();

// 绘制文本
ctx.font = "30px Arial";
ctx.fillStyle = "white";
ctx.fillText("Hello, World!", 50, 50);

// 绘制图像
var logo = new Image();
logo.src = "logo.png";
logo.onload = function() {
  ctx.drawImage(logo, 200, 200);
};

// 绘制按钮
var button = document.createElement("button");
button.innerHTML = "Click Me";
document.body.appendChild(button);