去掉<form>标签可执行，有无<form>标签的区别是？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>函数调用</title>
<script type="text/javascript">
function tcon()
{
alert("恭喜你学会函数调用了!");
}
</script>
</head>
<body>
<input type="button" value="点点我" onclick="tcon()">
</body>
</html>
