Ruby: Computed Style for a webpage

I'm using Hpricot to parse an html page, but need to get the computed styles for each element. F开发者_开发问答or example, if I have an h1 Hpricot element and the external CSS for the page has a background-image defined for h1's, how can I find out what the background-image is?

may be Selenium framework can help you?