改变HTML
1.改变HTML输出流
JavaScript可以创建动态的HTML内容。（注意：不要在加载文档后使用document.write()，这会覆盖文档。）
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>make HTML</title>
</head>
<body>
<script type="text/javascript">
document.write(Date());
</script>
</body>
</html>
2.改变HTML内容
使用innerHTML改变文档中元素内容。
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>change HTML</title>
</head>
<body>
<p id="demo">你好</p>
<button type="button" onclick="change()">点我改变内容</button>
<script>
function change(){
document.getElementById("demo").innerHTML="你也好呀";
}
</script>
</body>
</html>
3.改变HTML属性
//改变HTML属性语法 document.getElementById(id).attributte = new value;
<!DOCTYPE html>
<html>
<body>
<img id="image" src="smiley.gif">
<script>
document.getElementById("image").src="landscape.jpg";
</script>
</body>
</html>