Hey Coding Forums members, I've encountered a problem with the resizing of iframe when an ajax is loaded inside it - It wont resize. Is there anyway to fix this, or adding some codes to the iframe?

I'm using this script as my iframe resize:

Code:
            window.onload = function() {
                var f = document.getElementById("main","shoutbox");
                function resize() {
                    var h = "";
                    var w = "";
                    if (f.contentDocument) {
                        h = f.contentDocument.documentElement.offsetHeight + 20 + "px";
                        // can't find anything for Opera and Firefox that works for the width. OffetWidth doesn't work right either.(f.contentDocument.documentElement,"").getPropertyValue("width");
                    } else if (f.contentWindow) {
                        h = f.contentWindow.document.body.scrollHeight + 5 + "px";
                    } else {
                        return;
                    }
                    f.setAttribute("height",h);
                    f.parentNode.setAttribute("height",h);
                }
                if (window.addEventListener) {
                    f.onload = resize;
                } else if (f.attachEvent) {
                    f.attachEvent("onload", resize);
                } else {
                    return;
                }
                resize();
            }