iframe中div展开后页面如何自动变高

function change_size()
{
document.getElementById("info_iframe").style.height=info_content.document.body.scrollHeight+1+"px";
}<iframe marginheight="0" marginwidth="0" src="table.html" frameborder="0" scrolling="no" width="553" id="info_iframe" name="info_content" onload="change_size()"></iframe>