验证文件上传扩展名及重置

         $(":file").not("#<%= fuPFZipFile.ClientID %>").live("change", function () {
                var curId = $(this).attr("id");
                if (!CheckFileType(curId)) {
                    var domObj = $("#" + curId)[0];
                    domObj.outerHTML = domObj.outerHTML;
                }
                else {
                    hasUnSavedChanges = true;
                }
            });

        function CheckFileType(id) {
            if (document.getElementById(id).value.replace(/\s/g, "") != "") {
                var FileType = "gif,jpg,jpeg,bmp,png";
                var FileName = document.getElementById(id).value;
                FileName = FileName.substring(FileName.lastIndexOf(‘.‘) + 1, FileName.length).toLowerCase();
                if (FileType.indexOf(FileName) == -1) {
                    return false;
                }
                else {
                    return true;
                }
            }
        }