JS未跨域操作iframe里的DOM

index-><div class="d1"><iframe src="a.html" frameborder="0" name="one" id="iframeId"></iframe></div>

<div id="dd"><h1>iframe里的元素！</h1></div> 

var d=window.frames["one"].window;d.onload=function(){console.log(d.document.getElementById("dd"));}; 

var ifr = document.createElement('iframe');ifr.src = 'a.html';document.body.appendChild(ifr);ifr.onload = function(){var doc = ifr.contentDocument || ifr.contentWindow.document;// 在这里操纵b.htmlconsole.log(doc.getElementById("dd"));};