As stated in the urllib2 documentation:

The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.

So you should instead be saying

from urllib.request import urlopen
html = urlopen("").read()

Your current, now-edited code sample is incorrect because you are saying urllib.urlopen("") instead of just urlopen("").