20190225课练
使用JavaScript输出helloworld
…
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript简介</title>
</head>
<body>
<script type="text/javascript">
document.write("<h1>HELLO WORLD</h1>")
</script>
</body>
</html>
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使用外部引用，实现对话弹框
…
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript简介</title>
</head>
<body>
<script type="text/javascript">
document.write("<h1>HELLO WORLD</h1>")
alert("好好学习JavaScript技术");//
</script>
</body>
</html>
