Iframeページの高さを取得するjavascript

<iframe id="contentframe" src="@ViewBag.Url" height="1000px" frameborder="0" width="100%" allowtransparency scrolling="no">

</iframe>

<script type="text/javascript">



    $(function () {

        try {

            var frame = document.getElementById("contentframe");

            frame.onreadystatechange = function () {

                if (this.readyState == "complete")



                    var ifm = document.getElementById("contentframe");

                var subWeb = document.frames ? document.frames["contentframe"].document : ifm.contentDocument;

                if (ifm != null && subWeb != null) {

                    ifm.height = subWeb.body.scrollHeight;

                }

            }



        }

        catch (err) {            

            $("#contentframe").attr("height", 1000);

        }

    })

</script>