iframe frame 自动顺应所包含的页面大小

function SetWinHeight(obj) 
{ 
		var win=obj; 
		if (document.getElementById) 
		{ 
		if (win && !window.opera) 
		{ 
			if (win.contentDocument && win.contentDocument.body.offsetHeight) 
				win.height = win.contentDocument.body.offsetHeight; 
			else if(win.Document && win.Document.body.scrollHeight) 
				win.height = win.Document.body.scrollHeight; 
		} 
		} 
}