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");