自己写的_top、_parent以及对iframe和frameset的理解

iframe可以写在<body>标签里，如<body><iframe src="xxx" name="xxx" style="100%;height:500px;"/></body> iframe标签要成对，不然后面的标签不起作用

frameset不可以写在<body>标签里，如：

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	 <frameset rows="50%,25%,*"> 
	 	<frame name="frameset_target" src="./HelloWorld.html" noresize="noresize"/> 
	 	<frame src="/hello.java"/> 
	 	<frame src="/hello.java"/> 
	 </frameset>
</html>

-----------------------------------------------------------------------------------------------iframe

	<h5>iframe__frameset</h5> 
	<p><a href="V1.jpg" target="iframe_target">iframe</a></p> 
	<p><a href="V1.jpg" target="frameset_target">frameset</a></p>  
	<iframe src="/hello.java" name="iframe_target" style="100%;height:500px;"/>

-----------------------------------------------------------------------------------------------frameset

注：必须先将frameset所在页面打开，然后，再点击里面的超链接到frame里的标签，(frameset的子标签是frame，不是iframe)

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	 <frameset rows="50%,25%,*"> 
	 	<frame name="frameset_target" src="./HelloWorld.html" noresize="noresize"/> 
	 	<frame src="/hello.java"/> 
	 	<frame src="/hello.java"/> 
	 </frameset>
</html>

-----------------------------------------------------------------------------------------------top和parent

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<body>
		<a href="a_main.html">主界面</a>
	</body>
</html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	     <frameset rows="20%,*">
	     	<!--noresize属性规定用户无法调整框架的大小，默认是可以通过拖动框架之间的墙壁来改变框架大小-->
			<frame src="a_top.html" noresize="noresize"/>	  
			<frame src="a_bottom.html" name="bottom" noresize="noresize"/>	
	     </frameset>
</html>

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	<body>
	this is top.html     
	</body>   
</html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	     <frameset cols="20%,*">
	     	<!--noresize属性规定用户无法调整框架的大小，默认是可以通过拖动框架之间的墙壁来改变框架大小-->
			<frame src="a_left.html" noresize="noresize"/>	  
			<frame src="a_right.html" name="bottom" noresize="noresize"/>	
	     </frameset>
</html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	</head>
	<body>
	this is left.html
	</body>
</html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<title></title>
	</head>
	<body>
	this is right.html 
	<a href="a_target_test1.html" target="bottom">test1</a>
	<a href="a_target_test1.html" target="_parent">_parent</a>
	<a href="a_target_test1.html" target="_top">_top</a>
	</body>
</html>