start_urls = [
    'http://www.ebay.com/sch/i.html?_odkw=books&_osacat=0&_trksid=p2045573.m570.l1313.TR0.TRC0.Xpython&_nkw=python&_sacat=0&_from=R40'
    ]

def __init__(self):
    self.driver = webdriver.Firefox()

def parse(self, response):
    self.driver.get(response.url)
while True:
    next = self.driver.find_element_by_xpath('//td[@class="pagn-next"]/a')
try:
    next.click()
except:
    break
self.driver.close()
selenium with scrapy for dynamic page