这是您问题的答案：

您所说的元素find_element_by_id("submit-download- list")实际上是下载PDF文件。因此，为了将来程序员和该问题/帖子/线程/讨论的读者的利益，您可以考虑将问题标题更改为 Download and Save PDF file using selenium and python from popup

这是从弹出窗口使用selenium和python下载和保存PDF文件的代码块：

import os
from selenium import webdriver
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By

binary = FirefoxBinary('C:\\Program Files\\Mozilla Firefox\\firefox.exe')
newpath = 'C:\\home\\DebanjanB'
if not os.path.exists(newpath):
    os.makedirs(newpath)

profile = webdriver.FirefoxProfile()
profile.set_preference("browser.download.dir",newpath)
profile.set_preference("browser.download.folderList",2)
profile.set_preference("browser.helperApps.neverAsk.saveToDisk", "text/plain,text/x-csv,text/csv,application/vnd.ms-excel,application/csv,application/x-csv,text/csv,text/comma-separated-values,text/x-comma-separated-values,text/tab-separated-values,application/pdf")
profile.set_preference("browser.download.manager.showWhenStarting",False)
profile.set_preference("browser.helperApps.neverAsk.openFile","text/plain,text/x-csv,text/csv,application/vnd.ms-excel,application/csv,application/x-csv,text/csv,text/comma-separated-values,text/x-comma-separated-values,text/tab-separated-values,application/pdf")
profile.set_preference("browser.helperApps.alwaysAsk.force", False)
profile.set_preference("browser.download.manager.useWindow", False)
profile.set_preference("browser.download.manager.focusWhenStarting", False)
profile.set_preference("browser.helperApps.neverAsk.openFile", "")
profile.set_preference("browser.download.manager.alertOnEXEOpen", False)
profile.set_preference("browser.download.manager.showAlertOnComplete", False)
profile.set_preference("browser.download.manager.closeWhenDone", True)
profile.set_preference("pdfjs.disabled", True)

caps = DesiredCapabilities.FIREFOX
browser = webdriver.Firefox(firefox_profile=profile, capabilities=caps, firefox_binary=binary, executable_path='C:\\Utility\\BrowserDrivers\\geckodriver.exe')
browser.maximize_window()
browser.get("https://clinicaltrials.gov/ct2/results?cond=&term=lomitapide&cntry1=&state1=&SearchAll=Search+all+studies&recrs=")
browser.find_element_by_id("save-list-link").click()
download_link = WebDriverWait(browser, 10).until(
    EC.presence_of_element_located((By.XPATH, "//input[@id='submit-download-list']"))
)
download_link.click()

让我知道这是否回答了您的问题。