<script type="application/javascript">

function resizeIFrameToFitContent( iFrame ) {

    iFrame.width  = iFrame.contentWindow.document.body.scrollWidth;
    iFrame.height = iFrame.contentWindow.document.body.scrollHeight;
}

window.addEventListener('DOMContentLoaded', function(e) {

    var iFrame = document.getElementById( 'iFrame1' );
    resizeIFrameToFitContent( iFrame );

    // or, to resize all iframes:
    var iframes = document.querySelectorAll("iframe");
    for( var i = 0; i < iframes.length; i++) {
        resizeIFrameToFitContent( iframes[i] );
    }
} );

</script>

<iframe src="usagelogs/default.aspx" id="iFrame1"></iframe>

如果内容只是一个非常简单的html，最简单的方法是用javascript删除iframe

HTML代码:

<div class="iframe">
    <iframe src="./mypage.html" frameborder="0" onload="removeIframe(this);"></iframe>
</div>

Javascript代码:

function removeIframe(obj) {
    var iframeDocument = obj.contentDocument || obj.contentWindow.document;
    var mycontent = iframeDocument.getElementsByTagName("body")[0].innerHTML;
    obj.remove();
    document.getElementsByClassName("iframe")[0].innerHTML = mycontent;
}

跨浏览器jQuery插件。

cross -bowser, cross - domain library，使用mutationObserver来保持iFrame的大小与内容一致，使用postMessage在iFrame和主机页面之间进行通信。使用或不使用jQuery。

<script type="application/javascript">

function resizeIFrameToFitContent( iFrame ) {

    iFrame.width  = iFrame.contentWindow.document.body.scrollWidth;
    iFrame.height = iFrame.contentWindow.document.body.scrollHeight;
}

window.addEventListener('DOMContentLoaded', function(e) {

    var iFrame = document.getElementById( 'iFrame1' );
    resizeIFrameToFitContent( iFrame );

    // or, to resize all iframes:
    var iframes = document.querySelectorAll("iframe");
    for( var i = 0; i < iframes.length; i++) {
        resizeIFrameToFitContent( iframes[i] );
    }
} );

</script>

<iframe src="usagelogs/default.aspx" id="iFrame1"></iframe>

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>

以上方法均不能工作。

javascript:

function resizer(id) {
        var doc = document.getElementById(id).contentWindow.document;
        var body_ = doc.body, 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).style.height = height;
        document.getElementById(id).style.width = width;

    }

html:

<div style="background-color:#b6ff00;min-height:768px;line-height:inherit;height:inherit;margin:0px;padding:0px;overflow:visible" id="mainDiv"  >
         <input id="txtHeight"/>height     <input id="txtWidth"/>width     
        <iframe src="head.html" name="topFrame" scrolling="No" noresize="noresize" id="topFrame" title="topFrame" style="width:100%; height: 47px" frameborder="0"  ></iframe>
        <iframe src="left.aspx" name="leftFrame" scrolling="yes"   id="Iframe1" title="leftFrame" onload="resizer('Iframe1');" style="top:0px;left:0px;right:0px;bottom:0px;width: 30%; border:none;border-spacing:0px; justify-content:space-around;" ></iframe>
        <iframe src="index.aspx" name="mainFrame" id="Iframe2" title="mainFrame" scrolling="yes" marginheight="0" frameborder="0" style="width: 65%; height:100%; overflow:visible;overflow-x:visible;overflow-y:visible; "  onload="resizer('Iframe2');" ></iframe>
</div>

Env: IE 10, Windows 7 x64