function resizeIFrameToFitContent(frame) {
if (frame == null) {
    return true;
}

var docEl = null;
var isFirefox = navigator.userAgent.search("Firefox") >= 0;

if (isFirefox && frame.contentDocument != null) {
    docEl = frame.contentDocument.documentElement;
} else if (frame.contentWindow != null) {
    docEl = frame.contentWindow.document.body;
}

if (docEl == null) {
    return;
}

var maxWidth = docEl.scrollWidth;
var maxHeight = (isFirefox ? (docEl.offsetHeight + 15) : (docEl.scrollHeight + 45));

frame.width = maxWidth;
frame.height = maxHeight;
frame.style.width = frame.width + "px";
frame.style.height = frame.height + "px";
if (maxHeight > 20) {
    frame.height = maxHeight;
    frame.style.height = frame.height + "px";
} else {
    frame.style.height = "100%";
}

if (maxWidth > 0) {
    frame.width = maxWidth;
    frame.style.width = frame.width + "px";
} else {
    frame.style.width = "100%";
}
}

iFram风格：

.myIFrameStyle {
   float: left;
   clear: both;
   width: 100%;
   height: 200px;
   padding: 5px;
   margin: 0px;
   border: 1px solid gray;
   overflow: hidden;
}

iframe的日子:

<iframe id="myIframe" src="" class="myIFrameStyle"> </iframe>

脚本标签:

<script type="text/javascript">
   $(document).ready(function () {
      $('myIFrame').load(function () {
         resizeIFrameToFitContent(this);
      });
    });
</script>

我发现这个调整器工作得更好:

function resizer(id)
{

    var doc = document.getElementById(id).contentWindow.document;
    var body_ = doc.body;
    var html_ = doc.documentElement;

    var height = Math.max( body_.scrollHeight, body_.offsetHeight, html_.clientHeight,     html_.scrollHeight, html_.offsetHeight );
    var width  = Math.max( body_.scrollWidth, body_.offsetWidth, html_.clientWidth, html_.scrollWidth, html_.offsetWidth );

    document.getElementById(id).height = height;
    document.getElementById(id).width = width;

}

注意，样式对象被删除了。

如果你正在寻找一个没有jQuery跨起源的解决方案，你可能想看看我的想法:

<main id="container"></main>
<script>
  fetch('https://example.com').then(response => {
    return response.text();
  }).then(data => {
    const iframeContainer = window.document.getElementById('container');
    const iframe = document.createElement('iframe');
    iframe.frameBorder = 'none';
    iframe.width = '100%';
    iframe.addEventListener("load", function() {
      iframe.height = iframe.contentWindow.document.body.scrollHeight;
    })
    const finalHtml = data;
    const blob = new Blob([finalHtml], {type: 'text/html'});
    iframe.src = window.URL.createObjectURL(blob);
    iframeContainer.appendChild(iframe);
  })
</script>

到目前为止给出的所有解决方案都只考虑一次调整大小。您提到希望能够在修改内容后调整iFrame的大小。为此，您需要在iFrame中执行一个函数(一旦内容被更改，您需要触发一个事件来说明内容已更改)。

我被这个问题困扰了一段时间，因为iFrame内的代码似乎仅限于iFrame内的DOM(并且不能编辑iFrame)，而在iFrame外执行的代码则被iFrame外的DOM卡住(并且不能从iFrame内接收事件)。

解决方案来自于发现(通过同事的帮助)jQuery可以被告知使用什么DOM。在本例中，父窗口的DOM。

因此，这样的代码做了你所需要的(当在iFrame中运行时):

<script type="text/javascript">
    jQuery(document).ready(function () {
        jQuery("#IDofControlFiringResizeEvent").click(function () {
            var frame = $('#IDofiframeInMainWindow', window.parent.document);
            var height = jQuery("#IDofContainerInsideiFrame").height();
            frame.height(height + 15);
        });
    });
</script>

下面是一个跨浏览器的解决方案，如果你不想使用jQuery:

/**
 * Resizes the given iFrame width so it fits its content
 * @param e The iframe to resize
 */
function resizeIframeWidth(e){
    // Set width of iframe according to its content
    if (e.Document && e.Document.body.scrollWidth) //ie5+ syntax
        e.width = e.contentWindow.document.body.scrollWidth;
    else if (e.contentDocument && e.contentDocument.body.scrollWidth) //ns6+ & opera syntax
        e.width = e.contentDocument.body.scrollWidth + 35;
    else (e.contentDocument && e.contentDocument.body.offsetWidth) //standards compliant syntax – ie8
        e.width = e.contentDocument.body.offsetWidth + 35;
}

如果你可以控制IFRAME内容和父窗口，那么你需要IFRAME调整器。

这个库允许自动调整相同域和跨域iframe的高度和宽度，以适应它们所包含的内容。它提供了一系列功能来解决使用iFrames时最常见的问题，包括:

Height and width resizing of the iFrame to content size. Works with multiple and nested iFrames. Domain authentication for cross domain iFrames. Provides a range of page size calculation methods to support complex CSS layouts. Detects changes to the DOM that can cause the page to resize using MutationObserver. Detects events that can cause the page to resize (Window Resize, CSS Animation and Transition, Orientation Change and Mouse events). Simplified messaging between iFrame and host page via postMessage. Fixes in page links in iFrame and supports links between the iFrame and parent page. Provides custom sizing and scrolling methods. Exposes parent position and viewport size to the iFrame. Works with ViewerJS to support PDF and ODF documents. Fallback support down to IE8.