點評：html5可以畫很多種形狀，下面是畫矩形代碼分享，大家參考使用吧
<!DOCTYPE html><head>
<meta charset=utf-8>
<title>HTML5畫矩形</title>
<script src="<a href="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script">"></script</a>>
</head>
<script>
$(document).ready(function(){
var c=document.getElementById("drawbox");
var draw=c.getContext("2d");//獲取2d內容的引用，調用繪圖API
draw.fillStyle="#ff0000";//方式一指定填充顏色
draw.fillRect(0,0,300,100);//坐標和長寬
draw.fillStyle="rgba(0,0,255,0.5)"; //方式二rgb+透明度
draw.fillRect(400,0,100,100);//坐標和長寬
})
</script>
</body>
<canvas></canvas>
</body>
</html>
效果圖