据我了解，带有“ showRound” id的 td 的内部HTML是动态的，并由 showRound（） JS函数加载，该JS函数又被调用按页面加载时页面 head 标记中的脚本。因此，在您的情况下，似乎没有足够的时间来加载。我试图通过两种方式解决此问题：

1. 一个讨厌的人：使用 driver.implicitly_wait（number_of_seconds_to_wait）。我也建议将来使用它代替 sleep（）。但是，这种解决方案非常笨拙，并且是异步的。换句话说，它主要等待秒倒数而不是结果。

2. 我们可以等待第一个具有“ lsm2”类的元素加载；如果在合理的超时后仍未这样做，我们可能会停止等待并提出例外要求（感谢 Zeinab Abbasimazar 来回答here）。这可以通过 expected_conditions 和 WebDriverWait

来实现。

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

def pack_links(l):
    options = webdriver.ChromeOptions()  # I would also suggest to use this instead of Options()
    options.add_argument("--headless")
    options.add_argument("--enable-javascript")  # To be on the safe side,although it seems to be enabled by default
    driver = webdriver.Chrome("path_to_chromedriver_binary",options=options)
    driver.get(l)
    rnds = driver.find_element_by_id('showRound')

    """Until now,your code has gone almost unchanged. Now let's wait for the first td element with lsm2 class to load,with setting maximum timeout of 5 seconds:"""

    try:
        WebDriverWait(driver,5).until(EC.presence_of_element_located((By.CLASS_NAME,"lsm2")))
        print("All necessary tables have been loaded successfully")
    except TimeoutException:
        raise("Timeout error")


    """Then we proceed in case of success:"""

    a_ = rnds.find_elements_by_xpath(".//td[@class='lsm2']")
    knt = 0
    for _ in a_:
        knt = knt+1

    print(knt)

    driver.implicitly_wait(2)  # Not sure if it is needed here anymore
    driver.close()
    driver.quit()  # I would also recommend to make sure you quit the driver not only close it if you don't want to kill numerous RAM-greedy Chrome processes by hand 
    return None

您可以进行一些实验并调整超时时间，以达到所需的结果。我也建议使用 len（a _）而不是使用 for 循环进行迭代，但这取决于您。