javascript设置iframe高度自适应

<div class="right-nav">
    <iframe id="my-frame" name="my-frame" src="" frameborder="0" scrolling="auto" ></iframe>
</div>

<div class="clear"></div>

<div class="footer">&copy;</div>

<script>
    $(document).ready(function () {

        $("#my-frame").load(function(){
            var thisheight = $(this).contents().find("body").height() + 30;
            $(this).height(thisheight < 500 ? 500 : thisheight);
        });

    });

</script>