document.getElementsByTagName("body")[0].style.overflow = "hidden";
document.getElementsByTagName("html")[0].style.overflow = "hidden";

window.onresize = resize_iframe;
function resize_iframe() {

  var viewportwidth;
  var viewportheight;
  var header = document.getElementById("iframe_id").offsetTop;
  // the more standards compliant browsers (mozilla/netscape/opera) use window.innerWidth and window.innerHeight
  if (typeof window.innerWidth != 'undefined') {
    viewportwidth = window.innerWidth,
    viewportheight = window.innerHeight
    viewportheight = viewportheight - header;
  }

  // IE6,IE7 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
  else if (typeof document.documentElement != 'undefined' && typeof document.documentElement.clientWidth != 'undefined' && document.documentElement.clientWidth != 0) {
    viewportwidth = document.documentElement.clientWidth,
    viewportheight = document.documentElement.clientHeight
    viewportheight = viewportheight - header;
  }

  // older versions of IE
  else {
    viewportwidth = document.getElementsByTagName('body')[0].clientWidth,
    viewportheight = document.getElementsByTagName('body')[0].clientHeight
    viewportheight = viewportheight - header;
  }

  //document.write('<p>Your viewport width is '+viewportwidth+'x'+viewportheight+'</p>');
  var header = document.getElementById("iframe_id").offsetTop;
  document.getElementById("iframe_id").style.height=viewportheight+"px";
}