<!--// resize iframe 開始 //-->
function resizeBannerSide(){
  var ifr = document.getElementById("bannerside");
  var ifrBody = ifr.contentWindow.document[getDocBody(ifr.contentWindow)];
  ifr.style.height=0;
  ifr.style.height=(ifrBody.scrollHeight+10)+"px";
}


function getDocBody(win){
  if (!win) win=window;
  if (win.document.compatMode && win.document.compatMode != 'BackCompat') { //standards compliant mode 
    return "documentElement";
  }
  return "body";
}
<!--// resize iframe 結束 //-->