The urllib module allows you to access web pages in the same way that you access files. There are two modules of main interest: urllib.request contains functions to access Internet content, and urllib.error contains definition for exceptions that can be raised. You can also use urllib to communicate with webpages; if you want to do so, you need to study the urllib.parse module. For now, I only give a simple example in which you want to open a webpage and read its contents.

from urllib.request import urlopen
from urllib.error import HTTPError, URLError
from sys import exit

try:
    u = urlopen( "http://www.python.org" )
except HTTPError as e:
    print( "HTTP Error", e )
    sys.exit()
except URLError as e:
    print( "URL error", e )
    sys.exit()

for i in range( 5 ):
    text = u.readline()
    print( text )

u.close()

Note that from urllib only urlopen needs to be imported. Once you have opened a web address, it is returned as a file handle, so you can use the regular file methods on it.