Selenium Python3 - 无法按名称找到元素

Question

The code of the HTML element is as follows:

<input aria-label="Phone number, username, or email" aria-required="true" autocapitalize="none" autocorrect="off" maxlength="75" name="username" type="text" class="_2hvTZ pexuQ zyHYP" value="">

selenium.common.exceptions.NoSuchElementException: Message: Unable to locate element: [name="username"]

I get the error above when I execute this code:

from selenium.webdriver import Firefox

class Efrit:

    #Initializing the bot
    def __init__(self, username, password):
        self.username = username    # it could also be e-mail or phone number
        self.password = password

#Credentials to log into Instagram:
    def log(self):
        driver = Firefox('/usr/local/bin')
        driver.get("https://www.instagram.com/")
        username_location = driver.find_element_by_name('username')
        password_location = driver.find_element_by_name('password')

bot = Efrit('test, 'test')
bot.log()

Answer 1

You can use explicit wait:

from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

driver.get("https://www.instagram.com/")
wait = WebDriverWait(driver, 20)
            wait.until(EC.visibility_of_element_located((SelectBy.CSS, "/input[name=username]")))
        username_location = driver.find_element_by_css_selector('input[name=username]')
        password_location = driver.find_element_by_css_selector('input[name=password]')

To wait for login button use element_to_be_clickable

wait.until(EC.element_to_be_clickable(
                (SelectBy.CSS_SELECTOR, ".sqdOP.L3NKy.y3zKF")))
login = driver.find_element_by_css_selector(".sqdOP.L3NKy.y3zKF")
login.click()

You can also set the global implicit wait. https://selenium-python.readthedocs.io/waits.html (refer to P.5.2 for instructions).

Answer 2

As said in the comments by JaSON, the login form is not in page source and it takes time to render. You have to use wait

Explicit Wait

from selenium.webdriver import Firefox
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import TimeoutException

    class Efrit:
        #Initializing the bot
        def __init__(self, username, password):
            self.username = username    # it could also be e-mail or phone number
            self.password = password
    
    #Credentials to log into Instagram:
        def log(self):
            driver = Firefox('/usr/local/bin')
            driver.get("https://www.instagram.com/")
            delay = 6 # seconds
            try:
                username_location = WebDriverWait(driver, delay).until(EC.presence_of_element_located((By.NAME, 'username')))
                password_location = driver.find_element_by_name('password')
                print(username_location, password_location)
            except TimeoutException:
                print("Loading took too much time!")
            driver.quit()
    
    bot = Efrit('test', 'test')
    bot.log()