diff --git a/scripts/background/extractor.js b/scripts/background/extractor.js
index 3c9162f..a37f89f 100644
--- a/scripts/background/extractor.js
+++ b/scripts/background/extractor.js
@@ -113,14 +113,12 @@ class Extractor {
         let id = this._checkTaskId(taskid, this._tasks.length - 1);
         if (id < 0) return;
         let results = this._tasks[id].results
-        results.unshift(this._tasks[id].fieldSelectors);
-
-        let exResults = new ExtractResult(results);
-
         if (!results.length) {
             logger.info(`No result for task #${id}. Forget to call ".start()"?`);
             return;
         }
+        results.unshift(this._tasks[id].fieldSelectors);
+        let exResults = new ExtractResult(results);
         let msg = `
 Please confirm to download (${results.length - 1} items)：
 
diff --git a/scripts/background/result.js b/scripts/background/result.js
index 0d11fc2..b17894a 100644
--- a/scripts/background/result.js
+++ b/scripts/background/result.js
@@ -21,6 +21,9 @@ class ExtractResult {
         let data = rowsCount > 0 ? this._data.slice(0, rowsCount) : this._data;
         return data.slice().reduce(
             (csv, lineCells) => {
+                if (!lineCells || !lineCells.length) {
+                    return csv + "\n";
+                }
                 let line = lineCells.reduce(
                     (lineText, cell, idx) => {
                         cell = '"' + cell.trim().replace(/"/g, '""') + '"';