update readme

readme.md

@@ -185,6 +185,23 @@ e.start();
 
 > The uploaded state will be cleaned in 30 seconds, if you don't load it.
 
+## Watch Mode
+
+Watch mode tries to exract data from every page you visit **in current window**.
+
+```js
+e = new Extractor();
+e.task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
+    .task('list-item', ["a.title", "p.content"]);
+e.watch(1); // start watching for first task
+```
+
+To stop watching, you can either `close current window`, or:
+
+```js
+e.stop();
+```
+
 ## Developpment
 
 Clone this project and execute: