跨域文档之间的访问

<iframe id='iframe1' src="http://www.cnblogs.com/lydialee/p/4869145.html" frameborder="1"></iframe>

<script>
var iframe = document.getElementById('iframe1'); console.log('iframe',iframe);
var win = iframe.contentWindow; console.log('win',win);
var doc = win.document;  console.log('iframe document',doc);
window.onload = function (){
    console.log('document.domain:',document.domain);
    var iframe = document.getElementById('iframe1'); console.log('iframe',iframe);
    var win = iframe.contentWindow; console.log('win',win);
    var doc = win.document;  console.log('iframe document',doc);
}

执行结果

 window.onload中执行的结果：