https://developer.mozilla.org/en/DOM/window.postMessage

window.postMessage() window.postMessage is a method for safely enabling cross-origin communication. Normally, scripts on different pages are only allowed to access each other if and only if the pages which executed them are at locations with the same protocol (usually both http), port number (80 being the default for http), and host (modulo document.domain being set by both pages to the same value). window.postMessage provides a controlled mechanism to circumvent this restriction in a way which is secure when properly used. Summary window.postMessage, when called, causes a MessageEvent to be dispatched at the target window when any pending script that must be executed completes (e.g. remaining event handlers if window.postMessage is called from an event handler, previously-set pending timeouts, etc.). The MessageEvent has the type message, a data property which is set to the string value of the first argument provided to window.postMessage, an origin property corresponding to the origin of the main document in the window calling window.postMessage at the time window.postMessage was called, and a source property which is the window from which window.postMessage is called. (Other standard properties of events are present with their expected values.)

iFrame- resizzer库使用postMessage来保持iFrame的大小与其内容一致，并使用MutationObserver来检测内容的变化，而不依赖于jQuery。

https://github.com/davidjbradshaw/iframe-resizer

jQuery:跨域脚本的优点

http://benalman.com/projects/jquery-postmessage-plugin/

有调整iframe窗口大小的演示…

http://benalman.com/code/projects/jquery-postmessage/examples/iframe/

这篇文章展示了如何消除对jQuery的依赖…Plus有很多有用的信息和链接到其他解决方案。

http://www.onlineaspect.com/2010/01/15/backwards-compatible-postmessage/

Barebones操作...

http://onlineaspect.com/uploads/postmessage/parent.html

HTML 5工作草案在window.postMessage

http://www.whatwg.org/specs/web-apps/current-work/multipage/comms.html#crossDocumentMessages

John Resig谈跨窗口消息传递

http://ejohn.org/blog/cross-window-messaging/

找不到能完美处理大文本+大图像的东西，但我最终得到了这个，似乎这是对的，或者几乎是对的，每一次:

    iframe.addEventListener("load",function(){
        // inlineSize, length, perspectiveOrigin, width
        let heightMax = 0;
        // this seems to work best with images...
        heightMax = Math.max(heightMax,iframe.contentWindow.getComputedStyle(iframe.contentWindow.document.body).perspectiveOrigin.split("px")[0]);
        // this seems to work best with text...
        heightMax = Math.max(heightMax,iframe.contentWindow.document.body.scrollHeight);
        // some large 1920x1080 images always gets a little bit off on firefox =/
        const isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
        if(isFirefox && heightMax >= 900){
            // grrr..
            heightMax = heightMax + 100;
        }

        iframe.style.height = heightMax+"px";
        //console.log(heightMax);
    });

This is slightly tricky as you have to know when the iframe page has loaded, which is difficuly when you're not in control of its content. Its possible to add an onload handler to the iframe, but I've tried this in the past and it has vastly different behaviour across browsers (not guess who's the most annoying...). You'd probably have to add a function to the iframe page that performs the resize and inject some script into the content that either listens to load events or resize events, which then calls the previous function. I'm thinking add a function to the page since you want to make sure its secure, but I have no idea how easy it will be to do.

获取iframe内容高度，然后将其赋给这个iframe

 var iframes = document.getElementsByTagName("iframe");
 for(var i = 0, len = iframes.length; i<len; i++){
      window.frames[i].onload = function(_i){
           return function(){
                     iframes[_i].style.height = window.frames[_i].document.body.scrollHeight + "px";
                     }
      }(i);
 }

使用jQuery的最简单方法:

$("iframe")
.attr({"scrolling": "no", "src":"http://www.someotherlink.com/"})
.load(function() {
    $(this).css("height", $(this).contents().height() + "px");
});

最后，我找到了一些其他的解决方案，从iframe使用窗口发送数据到父网站。postMessage(消息、targetOrigin);。下面我来解释一下我是怎么做到的。

站点A = http://foo.com 站点B = http://bar.com

sitb在网站内部加载

SiteB网站有这条线

window.parent.postMessage("Hello From IFrame", "*"); 

or

window.parent.postMessage("Hello From IFrame", "http://foo.com");

然后site ea有如下代码

// Here "addEventListener" is for standards-compliant web browsers and "attachEvent" is for IE Browsers.
var eventMethod = window.addEventListener ? "addEventListener" : "attachEvent";
var eventer = window[eventMethod];


var messageEvent = eventMethod == "attachEvent" ? "onmessage" : "message";

// Listen to message from child IFrame window
eventer(messageEvent, function (e) {
   alert(e.data);
   // Do whatever you want to do with the data got from IFrame in Parent form.
}, false); 

如果你想添加安全连接，你可以在事件输入中使用这个If条件(messageEvent, function (e) {})

if (e.origin == 'http://iframe.example.com') {
    alert(e.data); 
    // Do whatever you want to do with the data got from IFrame in Parent form.
}

对于IE

IFrame内:

 window.parent.postMessage('{"key":"value"}','*');

外:

 eventer(messageEvent, function (e) {
   var data = jQuery.parseJSON(e.data);
   doSomething(data.key);
 }, false);