How to disable a "Reload site? Changes you made may not be saved" popup for (python) selenium tests in chrome?

This popup with text as Reload site? Changes you made may not be saved is the implementation of onbeforeunload property of WindowEventHandlers

onbeforeunload

The onbeforeunload property of the WindowEventHandlers mixin is the EventHandler for processing beforeunload events. These events fire when a window is about to unload its resources. At this point, the document is still visible and the event is still cancelable.

Solution

There are different strategies available to handle this popup.

• Chrome solution: Using --disable-popup-blocking through ChromeOptions():

  from selenium import webdriver
  
  options.add_argument("--disable-popup-blocking")
  driver=webdriver.Chrome(chrome_options=options, executable_path=/path/to/chromedriver')
  

• Firefox solution: Using dom.disable_beforeunload through FirefoxProfile():

  from selenium import webdriver
  profile = webdriver.FirefoxProfile()
  profile.set_preference("dom.disable_beforeunload", True)
  driver = webdriver.Firefox(firefox_profile = profile)
  

• Cross Browser solution: As a Cross Browser solution, you can disable this dialog invoking the executeScript() to set window.onbeforeunload as function() {}; and you can use the following solution:

  driver.execute_script("window.onbeforeunload = function() {};")
  

• JQuery based solution:

  $I->executeJS( "window.onbeforeunload = null" );
  

You can find a relevant discussion in How to handle below Internet Explorer popup “Are you sure you want to leave this page?” through Selenium

I know this doesn't answer the suppression part of the question, but..

Try this piece of code for accepting the popup:

driver.SwitchTo().Alert().Accept();