Trying to find image url via xpath using Mechanize
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I am trying to find the image xpath for the following page: http://www.spoonsisters.com/product/1032000/38710.html

I can view the image_url via my browser, however when I try finding it via Mechanize:

    page = Agent.get("http://www.spoonsisters.com/product/1032000/38710.html")
    page.parser.xpath('('//*[@id="main_image"]')')
     => [#<Nokogiri::XML::Element:0x80484c7c name="img" attributes=[#<Nokogiri::XML::Attr:0x80484bdc name="id" value="main_image">, #<Nokogiri::XML::Attr:0x80484bc8 name="src">, #<Nokogiri::XML::Attr:0x80484b8c name="alt" value="Paper Cocktail Napkins - What happens tonight goes on Facebook tomorrow">]>] 

I get 'src'> blank. How do I find the image_url?