Selenium click on popup button???

[Larz60+]

use XPath, and click()
example:

        search_box = browser.find_element(By.XPATH, '//*[@id="quickSearch_BusinessName"]')
        search_box.send_keys(searchitem)
        browser.find_element(By.XPATH, '//*[@id="btn_Search"]').click()
        time.sleep(2)

In Firefox, You can get the XPath of the button, by bringing up site, right click on button and select Inspect Element-->Copy-->XPath