How to save "complete webpage" not just basic html using Python

You can easily do that with simple python library pywebcopy.

For Current version: 5.0.1

from pywebcopy import save_webpage

url = 'http://some-site.com/some-page.html'
download_folder = '/path/to/downloads/'    

kwargs = {'bypass_robots': True, 'project_name': 'recognisable-name'}

save_webpage(url, download_folder, **kwargs)

You will have html, css, js all at your download_folder. Completely working like original site.

Try emulating your browser with selenium. This script will pop up the save as dialog for the webpage. You will still have to figure out how to emulate pressing enter for download to start as the file dialog is out of selenium's reach (how you do it is also OS dependent).

from selenium import webdriver
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys

br = webdriver.Firefox()
br.get('http://www.google.com/')

save_me = ActionChains(br).key_down(Keys.CONTROL)\
         .key_down('s').key_up(Keys.CONTROL).key_up('s')
save_me.perform()

Also I think following @Amber suggestion of grabbing the the linked resources may be a simpler, thus a better solution. Still, I think using selenium is a good starting point as br.page_source will get you the entire dom along with the dynamic content generated by javascript.