diff --git a/readme.md b/readme.md
index 584bed6..6d72bba 100644
--- a/readme.md
+++ b/readme.md
@@ -13,10 +13,14 @@ All you need to do is:
 ## Qucik Start
 
 Extract current page
+
 ```js
 $('.item', ['a', 'a@href']);
+new Extractor().task('.item', ['a', 'a@href']).start();
 ```
 
+> `$(...args)` is the short form of `new Extractor().task(...args).start();`, which is introduced later.
+
 Extract multiple pages (1-10, interval 1)
 
 ```js
@@ -54,6 +58,15 @@ function (itemsSelector:string, fieldSelectors:string[], urls:ExtractResult)
 
 Close the target tab, in which current tasks is running.
 
+Or use `job.stop()`:
+
+```js
+job = new Extractor().task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
+    .task('list-item', ["a.title", "p.content"])
+    .start();
+job.stop();
+```
+
 ## Extract Attributes.
 
 e.g.: link text and target (use 'selector@attribute')
diff --git a/src/background/extractor.ts b/src/background/extractor.ts
index f8acb7c..cd72c96 100644
--- a/src/background/extractor.ts
+++ b/src/background/extractor.ts
@@ -51,14 +51,19 @@ export class Extractor {
     /**
      * Start the task chain.
      */
-    async start() {
+    start() {
         return this._startTasks(0);
     }
+    stop() {
+        for (let i = 0; i < this._tasks.length; i++) {
+            this._tasks[i].stop();
+        }
+    }
     /**
      * restart from specified task, but don't restart the previous tasks.
      * @param {number} from where to restart the tasks, begins with 0
      */
-    async restart(from: number = 0) {
+    restart(from: number = 0) {
         let id = this._checkTaskId(from, 0);
         if (id < 0) return;
         for (let i = id; i < this._tasks.length; i++) {
diff --git a/src/background/task.ts b/src/background/task.ts
index a45b6ad..b99f91d 100644
--- a/src/background/task.ts
+++ b/src/background/task.ts
@@ -10,6 +10,7 @@ export class Task {
     private _itemsSelector: string;
     private _fieldSelectors: string[];
     private _urls: string[] = [];
+    private _running = false;
 
     constructor(options: any, ...arg: any);
     constructor(options: any, itemsSelector: string, fieldSelectors: string[]);
@@ -49,8 +50,13 @@ export class Task {
         this._data_keys = [];
         return this;
     }
+    stop() {
+        this._running = false;
+    }
     async execute(tab: chrome.tabs.Tab, upstreamData?: ExtractResult): Promise<void> {
         if (!tab) return Promise.reject("No tab to execute the task.");
+        if (this._running) return Promise.reject("The task is running. Please wait...");
+        this._running = true;
         let urls = this._urls
         if (!urls.length) {
             if (upstreamData) {
@@ -63,6 +69,10 @@ export class Task {
             this._data[key] = results;
             this._data_keys.push(key);
         }
+        let runningCheck = (fn: () => Promise<any>): Promise<any> => {
+            if (!this._running) return Promise.reject("The task is stopped by user.");
+            return fn();
+        }
         return urls.reduce((p, url, i) => p.then(
             results => {
                 if (i > 0 && results instanceof Array) {
@@ -70,12 +80,13 @@ export class Task {
                     saveResult(results, lastURL);
                 }
                 if (this._data[url]) return;
-                let pms: Promise<any> = redirectTab(tab, url);
+
+                let pms: Promise<any> = runningCheck(() => redirectTab(tab, url));
                 if (this._options["scrollToBottom"]) {
-                    pms = pms.then(() => scrollToBottom(tab));
+                    pms = pms.then(() => runningCheck(() => scrollToBottom(tab)));
                 }
                 return pms.then(
-                    () => extractTabData(tab, this._itemsSelector, this._fieldSelectors)
+                    () => runningCheck(() => extractTabData(tab, this._itemsSelector, this._fieldSelectors))
                 );
             }
         ), Promise.resolve<string[][]>(null)).then(
@@ -83,9 +94,14 @@ export class Task {
                 if (results && results.length) {
                     let lastURL = urls[urls.length - 1];
                     saveResult(results, lastURL);
-                    return;
+                    this._running = false;
                 }
             }
+        ).catch(
+            e => {
+                this._running = false;
+                return Promise.reject(e);
+            }
         );
     }
 }
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