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.

https://getbootstrap.com/docs/4.0/utilities/embed/

经过大量的研究，我明白了，这不是一个独特的问题，我打赌Bootstrap处理它。你瞧……

iGoogle小工具必须主动实现调整大小，所以我猜在跨域模型中，如果没有远程内容以某种方式参与，你就无法做到这一点。如果您的内容可以使用典型的跨域通信技术将具有新大小的消息发送到容器页面，那么其余部分就很简单了。

如果你不需要处理来自不同域的iframe内容，试试这段代码，它将完全解决问题，它很简单:

<script language="JavaScript">
<!--
function autoResize(id){
    var newheight;
    var newwidth;

    if(document.getElementById){
        newheight=document.getElementById(id).contentWindow.document .body.scrollHeight;
        newwidth=document.getElementById(id).contentWindow.document .body.scrollWidth;
    }

    document.getElementById(id).height= (newheight) + "px";
    document.getElementById(id).width= (newwidth) + "px";
}
//-->
</script>

<iframe src="usagelogs/default.aspx" width="100%" height="200px" id="iframe1" marginheight="0" frameborder="0" onLoad="autoResize('iframe1');"></iframe>

当你想缩小网页以适应iframe大小时:

您应该调整iframe的大小以适应内容 然后你应该缩小整个iframe与加载的网页内容

这里有一个例子:

<div id="wrap">
   <IFRAME ID="frame" name="Main" src ="http://www.google.com" />
</div>

<style type="text/css">
    #wrap { width: 130px; height: 130px; padding: 0; overflow: hidden; }
    #frame { width: 900px; height: 600px; border: 1px solid black; }
    #frame { zoom:0.15; -moz-transform:scale(0.15);-moz-transform-origin: 0 0; }
</style>

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);
    });