求助:setTimeout无效

JScript code

<script type="text/javascript">        var fileName = null;        var oldFileName = null;        setFileOnChange();                function upload() {            var oldAction = $('form_1').action;            $('form_1').action = "fileupload/fileUploadServlet.do";            $('form_1').method = "post";            $('form_1').enctype = "multipart/form-data";            $('form_1').target = "iframe_hidden";            oldFileName = getFileName();            $('form_1').submit();            addImg();            $('form_1').action = oldAction;            $('form_1').enctype = '';            $('form_1').target = 'self';        }        function getFileName(){            return fileName;        }                function setFileOnChange(){            $('file_img').onchange = function(){                fileName = this.value;            }        }                function isNewFile(){            if(oldFileName!=null && oldFileName != fileName){                return true;            }else{                return false;            }        }                function addImg(){            if(alreadyExist()&&isNewFile()){                changeImg();            }else{                append();            }        }                function changeImg(){            var node = $('img_1');            var oldSrc = node.src;            var newSrc = getImgHref();            if(oldSrc != newSrc){                node.src = newSrc;            }else{                setTimeout('changeImg()',1000);            }        }                function append() {            var _src = getImgHref();            if(_src!=null){                var node = document.createElement("img");                node.id='img_1';                node.src = _src;                node.width = "85";                node.height = "100";                $('td_img').appendChild(node);            }else{                setTimeout('append()',1000);            }        }                function alreadyExist(){            var node = $('img_1');            if(node != null){                return true;            }            return false;        }        function $(nodeId) {            return document.getElementById(nodeId);        }        function getIframe() {            var doc = null;            if (document.all) {//IE                doc = document.frames["iframe_hidden"].document;            } else {//Firefox                    doc = document.getElementById("iframe_hidden").contentDocument;            }            return doc;        }        function getImgHref() {            var node = getIframe().getElementById('hidden_imgHref');            if(node!=null){                var v = node.value;                return v;            }            return null;        }    </script>

主要是用来添加img节点的,应该递归的函数现在就执行了一次.不知道这setTimeout哪出了问题.跪求高手解答.

[解决办法]
看你判断条件。。你不是写在else 里面了嘛。。