iframe中的jquery ui modal dialog 覆盖父窗口参考

function openDialog(){
var $doc;
if(window.location!=window.parent.location){
// <SPAN style="COLOR: #ff0000">页面在iframe中</SPAN>
$doc=window.parent.jQuery.noConflict();
}else{
// <SPAN style="COLOR: #ff0000">页面单独打开</SPAN>
$doc=jQuery.noConflict();
}
$doc("body").append(‘<div id=dialog></div>‘);
var dialog=$doc("#dialog");
dialog.html("欢迎你");
dialog.dialog( {modal: true});
}