function iframeResizePipe(){
    var height = document.body.parentNode.scrollHeight;

    // Going to 'pipe' the data to the parent through the helpframe.
    var pipe = document.getElementById('helpframe');

    // Cachebuster a precaution here to stop browser caching interfering
    pipe.src = 'http://www.pdt.org.uk/helper.html?height='+height+'&cacheb='+Math.random();
}