Webscraping using Javascript

There are a number of Javascript frameworks you can use to web scraping:

1) Selenium, check out Seleinum Grid.
Selenium has been adopted as the primary technology for functional testong of web applications within Google.
Selenium now wraps htmlunit so you don´t need start a browser anymore. The new WebDriver api is very easy to use too. The first example use htmlunit driver
2) Watir (Ruby)
3) PhantomJS
4) CasperJS
5) Zombie for Node.js
6) Pjscrap based on PhantomJS and JQuery
7) HTMLUnit (Java)