我们也可以封装一下我们的矩形，代码如下：
JavaScript Code复制内容到剪贴板
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>封装绘制矩形方法</title>
</head>
<body>
<div id="canvas-warp">
<canvas id="canvas" style="border: 1px solid #aaaaaa; display: block; margin: 50px auto;">
你的浏览器居然不支持Canvas？！赶快换一个吧！！
</canvas>
</div>
<script>
window.onload = function(){
var canvas = document.getElementById("canvas");
canvas.width = 800;
canvas.height = 600;
var context = canvas.getContext("2d");
drawRect(context, 150, 50, 50, 50, "red", 5, "blue");
drawRect(context, 250, 50, 50, 50, "green", 5, "red");
drawRect(context, 350, 50, 50, 50, "yellow", 5, "black");
}
function drawRect(cxt, x, y, width, height, fillColor, borderWidth, borderColor){
cxt.beginPath();
cxt.moveTo(x, y);
cxt.lineTo(x + width, y);
cxt.lineTo(x + width, y + height);
cxt.lineTo(x, y + height);
cxt.lineTo(x, y);
cxt.closePath();
cxt.lineWidth = borderWidth;
