function resizeIFrame() { document.getElementById("content-iframe").height = document.body.offsetHeight - document.getElementById("wrapper-iframe").offsetTop; //resize the iframe according to the size of the window } window.onresize=resizeIFrame; //instead of using this you can use: function loadIFrame() { resizeIFrame(); newURL = unescape(document.location.search); newURL = newURL.replace(/.*\?message=(.*)/,'$1'); newURL = newURL.substring(1, newURL.length); window.frames['content-iframe'].location.href = newURL; imageSetup(); }