from bs4 import BeautifulSoup
s = requests.Session()
r = s.get("http://www.transtats.bts.gov/Data_Elements.aspx?Data=2")
soup = BeautifulSoup(r.text)
viewstate_element = soup.find(id="__VIEWSTATE")
viewstate = viewstate_element["value"]
eventvalidation_element = soup.find(id="__EVENTVALIDATION")
eventvalidation = eventvalidation_element["value"]
r = s.post("http://www.transtats.bts.gov/Data_Elements.aspx?Data=2",
data={'AirportList' : "BOS",
'CarrierList' : "VX",
'Submit' : "Submit",
'__EVENTTARGET' : "",
'__EVENTVALIDATION' : eventvalidation,
'__VIEWSTATE' : viewstate})
f = open("virgin_and_logan_airport.html", "w")
f.write(r.text)
