<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>document.write</title>
<script type="text/javascript">
var mystr="我是";
var mychar="JavaScript";
document.write(mychar+"<br>");
document.write(mastr+mychar+"的忠实粉丝！")；
</script>
</head>
<body>
</body>
</html>
thank you!
document.write(mastr+mychar+"的忠实粉丝！")；这行代码的mystr打错成mastr