resize_iframe_height.js

// Resize iframe height

jQuery(function(){
  var iframes = $('iframe.resize-to-max-height');

  var pageY = function (elem) {
    return elem.offsetParent ? (elem.offsetTop + pageY(elem.offsetParent)) : elem.offsetTop;
  }

  if (iframes.length){

    var resizeAllIframes = function(){
      var buffer = 20,
          height = document.documentElement.clientHeight,
          iframeHeight;

      iframes.each(function(idx, iframe){
        iframeHeight = height - (pageY(iframe) + buffer);
        iframeHeight = (iframeHeight < 0) ? 0 : iframeHeight;

        $(iframe).css({'height': iframeHeight + 'px'});
      });
    }

    window.onresize = resizeAllIframes;

    resizeAllIframes();
  }
});