python selenium execute script confirmation box, getting results back

I ran into the exact same problem. In javascript, confirm() is a blocking function. Other code waits for it to return. However, Selenium is somehow circumventing this, meaning the popup returns None right away.

driver.execute_script("return confirm('Do you like apples?');")

This is true for all three popup windows. (The values listed are what they are supposed to return).

• alert() returns None
• confirm() returns bool
• prompt() returns str

The way that you make them return properly is to assign their values to a preexisting variable.

driver.execute_script("let response;")
driver.execute_script("response = confirm('Do you like apples?');")

user_likes_apples = driver.execute_script("return response;")

This only works if you define response in an entirely seperate call. The following does not work.

driver.execute_script("let response; response = confirm('Do you like apples?');")
driver.execute_script("return response;")

Below I've developed a full example. Hope it's useful.

from typing import Optional

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
from selenium.common.exceptions import TimeoutException, NoSuchWindowException, NoAlertPresentException


class PopupDriver(webdriver.Chrome):
    # Show a popup in the browser
    def _show_popup(self, popup: str, message: str) -> Optional[object]:
        self.execute_script("let result;") # must be seperate
        self.execute_script("result = %s('%s');" % (popup, message))
        self.wait.until(EC.alert_is_present())
        
        # Function to determine whether user has closed alert
        def popup_is_closed(driver: webdriver.Chrome) -> bool:
            try: response = dir(self.switch_to.alert)
            except NoAlertPresentException: return True
            
            return False
        
        # Wait until alert is closed by user
        self.wait.until(popup_is_closed)
        
        # Return alert text value
        return self.execute_script("return result;")
    
    # Show an alert popup in the browser
    def show_alert(self, message: str) -> None:
        self._show_popup("alert", message)
    
    # Show a confirmation popup in the browser
    def show_confirmation(self, message: str) -> bool:
        return self._show_popup("confirm", message)
    
    # Show a prompt popup in the browser
    def show_prompt(self, message: str) -> str:
        return self._show_popup("prompt", message)
    
    # Oh so difficult
    def ask_the_hard_questions(self) -> None:
        self.show_alert("Hello world!")
        
        user_is_sane = self.show_confirmation("Continue if you think the world is a sphere.")
        
        print("You think that the Earth is ", "not " * user_is_sane, "flat.", sep="")
        print("Your name is", self.show_prompt(r"What\'s your name?")) # escape single quote
    
    # Handle exceptions
    def run(self) -> None:
        try: self.ask_the_hard_questions()
        except TimeoutException: # user did not respond within timeout
            try: self.show_alert("You timed out. Stumped, huh?")
            except TimeoutException: pass
        except NoSuchWindowException: pass # user closed the window
        finally: self.quit()
        

if __name__ == "__main__":
    p = PopupDriver()
    p.run()