js如何判断是否在iframe中及防止网页被别站用iframe嵌套

//方式一 
if (self.frameElement && self.frameElement.tagName == "IFRAME") { 
  alert('在iframe中'); 
} 
//方式二 
if (window.frames.length != parent.frames.length) { 
  alert('在iframe中'); 
} 
//方式三 
if (self != top) { 
 alert('在iframe中'); 
} 

<script language="javascript"> 
<!-- 
if (top.location != location) 
{ 
top.location.href = location.href; 
} 
//--> 
</script> 
//或 
<script language="javascript"> 
if(self!=top){top.location.href=self.location.href;} 
</script> 

<iframe src="你的页面地址" name="tv" marginwidth="0" marginheight="0" scrolling="No" noResize frameborder="0" id="tv" framespacing="0" width="580" height="550" VSPACE=-145 HSPACE=-385></iframe> 
<script language="javascript"> 
var location=""; 
var navigate=""; 
frames[0].location.href=""; 
</script> 

<script language="javascript"> 
if(top != self){ 
 location.href = "about:blank"; 
} 
</script> 

header("X-Frame-Options: deny"); 
header("X-XSS-Protection: 0");