<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>HTML5每日
<html><head><metahttp-equiv="Content-Type"content="text/html;charset=gb2312"><title>H...
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>HTML5每日一练之Canvas标签的应用-绘制复杂图形</title>
<script type="text/javascript">
alert("adsfa123");
var canvas = document.getElementById('canvas');
var context2D = canvas.getContext('2d');
alert("a333dsfa123");
</script>
</head>
<body>
<canvas id="canvas" width="600" height="400"></canvas>
</body>
</html>
第二个alert不管用，为什么？？？？ 展开
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>HTML5每日一练之Canvas标签的应用-绘制复杂图形</title>
<script type="text/javascript">
alert("adsfa123");
var canvas = document.getElementById('canvas');
var context2D = canvas.getContext('2d');
alert("a333dsfa123");
</script>
</head>
<body>
<canvas id="canvas" width="600" height="400"></canvas>
</body>
</html>
第二个alert不管用，为什么？？？？ 展开
2个回答
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