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+# DataExtracter Help
+----------------------------
+
+DataExtracter helps you quickly extract data from any web pages. All you need to do is:
+
+- Find out the selectors (JQuery selectors) for target data
+- Call Extractor methods in `extension backgroud page console`, as introduced bellow.
+
+Where is the extension backgroud page console?
+
+Goto <chrome://extensions/> and click `backgroud page` link of the extension
+
+ ![](images/extnsion.png)
+
+In the opening window, find `Console`, and type your scripts.
+
+ ![](images/console.png)
+
+## Qucik Start
+
+
+
+Extract current page
+```js
+new Extractor().task(".list-item", ["a.title", "p.content"]).start();
+```
+
+Extract multiple pages (1-10, interval 1)
+
+```js
+new Extractor().task(".list-item", ["a.title", "p.content"],"http://sample.com/?pn=${page}", 1, 10, 1).start();
+```
+
+Extract multiple urls (list)
+
+```js
+new Extractor().task(".list-item", ["a.title", "p.content"],["http://sample.com/abc","http://sample.com/xyz"]).start();
+```
+
+Extract specified pages (1,3,5)
+
+```js
+new Extractor().task(".list-item", ["a.title", "p.content"], "http://sample.com/?pn=${page}", [1, 3, 5]).start();
+```
+
+## Extractor.task() Signitures:
+
+```ts
+// a task extracting data from current page
+task(itemsSelector:string, fieldSelectors:string[])
+// a task extracting data from a range of pages
+task(itemsSelector:string, fieldSelectors:string[], urlTemplate:string, from:number, to:number, interval:number)
+// a task extracting data from a list of pages
+task(itemsSelector:string, fieldSelectors:string, urlTemplate:string, pages:number[])
+// a task extracting data from a list of pages
+task(itemsSelector:string, fieldSelectors:string[], urls:string[])
+// a task extracting data of urls which extracted from last task result
+task(itemsSelector:string, fieldSelectors:string[], urls:ExractResult)
+```
+
+## Advanced Usage:
+
+### Stop tasks
+
+The only way to stop tasks before its finish, is `Closing the Tab` which runs tasks.
+
+### Extract attributes. 
+
+e.g.: link text and target (use 'selector@attribute')
+
+```js
+new Extractor().task('.list-item', ['a.title', 'a.title@href']).start();
+```
+
+### Use task chain. 
+
+e.g.: Collect links from `http://sample.com/abc` & Extract data of each link
+
+```js
+new Extractor()
+    .task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+    .task('list-item', ["a.title", "p.content"])
+    .start();
+```
+
+### Save result of any task
+
+To a multiple task (chain) Extractor `e`:
+
+```js
+e = new Extractor()
+e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+    .task('list-item', ["a.title", "p.content"])
+    .start();
+```
+
+User will be asked to save  the final result when it finishes.
+
+You may want to save another task's result, other than the final:
+
+```js
+// save the result of first task
+// that is, a list of urls
+e.save(1)
+```
+
+Incase you want to save it again, use:
+
+```js
+e.save()
+```
+
+### Restart tasks
+
+In cases some later task fails, you don't need to restart all task.
+
+Here we have 2 tasks:
+
+```js
+e = new Extractor()
+e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
+    .task('list-item', ["a.title", "p.content"])
+    .start();
+```
+
+Suppose the second task fails, we can restart and continue from the task 2:
+
+```js
+e.restart(2);
+```
+
+If you'd like restart all task, use:
+
+```js
+e.start();
+// or
+e.restart();
+```