今天学习html5 的canvas，发现fillRect的坐标和大小一直不对，研究了半天，发现canvas的宽度和高度必须内联在canvas标签中才对。郁闷了半天。
错误的方式1:
复制代码代码如下:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
#mycanvas{
width: 200px;
height: 200px;
background: yellow;
}
</style>
</head>
<body>
<canvas id=mycanvas ></canvas>
<script>
var c = document.getElementById(mycanvas);
var ctx = c.getContext("2d");
ctx.fillStyle=#f36;
ctx.fillRect(100, 100, 100, 100);
</script>
</body>
</html>
错误的方式2：
复制代码代码如下:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<canvas id=mycanvas style=width:200px;height:200px;background:yellow></canvas>
<script>
var c = document.getElementById(mycanvas);
var ctx = c.getContext("2d");
ctx.fillStyle=#f36;
ctx.fillRect(100, 100, 100, 100);
</script>
</body>
</html>
显示结果：
正确的方式：
复制代码代码如下:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<canvas id=mycanvas width=200px height=200px style=background:yellow></canvas>
<script>
var c = document.getElementById(mycanvas);
var ctx = c.getContext("2d");
ctx.fillStyle=#f36;
ctx.fillRect(100, 100, 100, 100);
</script>
</body>
</html>
