How to parse html that includes javascript code

You can use Selenium with python as detailed here

Example:

import xmlrpclib

# Make an object to represent the XML-RPC server.
server_url = "http://localhost:8080/selenium-driver/RPC2"
app = xmlrpclib.ServerProxy(server_url)

# Bump timeout a little higher than the default 5 seconds
app.setTimeout(15)

import os
os.system('start run_firefox.bat')

print app.open('http://localhost:8080/AUT/000000A/http/www.amazon.com/')
print app.verifyTitle('Amazon.com: Welcome')
print app.verifySelected('url', 'All Products')
print app.select('url', 'Books')
print app.verifySelected('url', 'Books')
print app.verifyValue('field-keywords', '')
print app.type('field-keywords', 'Python Cookbook')
print app.clickAndWait('Go')
print app.verifyTitle('Amazon.com: Books Search Results: Python Cookbook')
print app.verifyTextPresent('Python Cookbook', '')
print app.verifyTextPresent('Alex Martellibot, David Ascher', '')
print app.testComplete()

From Mozilla Gecko FAQ:

Q. Can you invoke the Gecko engine from a Unix shell script? Could you send it HTML and get back a web page that might be sent to the printer?

A. Not really supported; you can probably get something close to what you want by writing your own application using Gecko's embedding APIs, though. Note that it's currently not possible to print without a widget on the screen to render to.

Embedding Gecko in a program that outputs what you want may be way too heavy, but at least your output will be as good as it gets.

PhantomJS can be loaded using Selenium

$ ipython

In [1]: from selenium import webdriver

In [2]: browser=webdriver.PhantomJS()

In [3]: browser.get('http://seleniumhq.org/')

In [4]: browser.title
Out[4]: u'Selenium - Web Browser Automation'