摘要：
1. 获得iframe的window对象存在跨域访问限制。chrome：iframeElement. contentWindow firefox： iframeElement.contentWindow ie6：iframeElement.contentWindow文章Iframes, onload, and document.domain中说“he iframe element object has a property called contentDocument that contains the iframe’s document object, so you can use the 阅读全文
