打开html页面并重写其内容

Question

如何打开现有的html页面并重写其内容？这不起作用：

var left = (screen.width / 2) - 200;
var top = (screen.height / 2) - 200;
var win = window.open("http://someexistinurl.com/embed.html","_blank","width=400,height=400,status=1,resizeable=1,top="+top+ ",left="+left);
win.document.open("text/html", "replace");
win.document.write("<center>Error</center>");
win.document.close();
win.focus();
return win.document.body;