How to test non-standard drop down lists through a crawler using Selenium and Python

问题

I am in a university project building a cralwer for webpages. Now I encountered testing dropdown lists in webpage. Specifically, the following page does not use the standard "dropdown" class.

https://www.mirrorfiction.com/zh-Hant/book/406

I have difficulties implementing a decision procedure to tell whether there are dropdowns in the webpage and whether the dropdowns have been dropped down.

The programmers seem to use a class called btnGa or something alike. I cannot google that.
I have no clue how a browser would know the dropdown tags.
The html source is too big. So I only copied a small part in the following.
The html source contains a ul of navlist class. Then an li tag in this ul contains another ul which is actually a dropdown list at hovering.
But I really cannot see how the browser would know that this is a dropdown list. Thus I don't know how to write a test case to click the buttons in this dropdown list.

Can any one help me out in recognizing the dropdown lists and click the dropdown list items ?

HTML:

<ul class="navList">
    <li class="mobileDisable">
        <a data-ga-label="小說" data-ga-action="click" data-ga-category="header" onclick="app.navLiClick(this)" class="hasSub btnGa open" href="https://www.mirrorfiction.com/zh-Hant/list/novel">
            <span class="text novel">小說</span>
        </a>
        <ul>
            <li>
                <a data-ga-label="小說-仙俠" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/11">
                        <span class="text">仙俠</span>
                        <span class="num">/ 16</span>
                    </a>
                </li>
                <li>
                    <a data-ga-label="小說-玄幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/9">
                        <span class="text">玄幻</span>
                        <span class="num">/ 24</span>
                    </a>
                </li>
                <li>
                    <a data-ga-label="小說-奇幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/29">
                        <span class="text">奇幻</span>
                        <span class="num">/ 56</span>
                     </a>
                                </li>
                                                            <li>
                     <a data-ga-label="小說-武俠" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/10">
                         <span class="text">武俠</span>
                         <span class="num">/ 11</span>
                      </a>
                  </li>
                                                            <li>
                  <a data-ga-label="小說-科幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/8">
                       <span class="text">科幻</span>
                       <span class="num">/ 17</span>
                  </a>
              </li>
                                                            <li>
              <a data-ga-label="小說-恐怖" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/30">
                       <span class="text">恐怖</span>
                       <span class="num">/ 11</span>
              </a>
            </li>
                                                            <li>
           <a data-ga-label="小說-校園" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/7">
                  <span class="text">校園</span>
                  <span class="num">/ 16</span>
                </a>
            </li>
                                                            <li>
            <a data-ga-label="小說-愛情" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/1">
                  <span class="text">愛情</span>
                  <span class="num">/ 78</span>
               </a>
            </li>
                                                            <li>
            <a data-ga-label="小說-寫實" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/5">
                  <span class="text">寫實</span>
                  <span class="num">/ 48</span>
                </a>
            </li>
                                                            <li>
                                    <a data-ga-label="小說-歷史" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/6">
                                        <span class="text">歷史</span>
                                        <span class="num">/ 13</span>
                                    </a>
                                </li>
                                                            <li>
                                    <a data-ga-label="小說-驚悚" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/31">
                                        <span class="text">驚悚</span>
                                        <span class="num">/ 24</span>
                                    </a>
                                </li>
                                                            <li>
                                    <a data-ga-label="小說-其它" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/12">
                                        <span class="text">其它</span>
                                        <span class="num">/ 40</span>
                                    </a>
                                </li>
                                                    </ul>
                    </li>

回答1:

Consider following the steps & lines of code to open the url & click on a menu:

• Install current version of selenium through pip
• Download the latest chromedriver.exe and provide the absolute path in your script

• Code Block:

  from selenium import webdriver
  driver=webdriver.Chrome("C:\\Utility\\your_directory\\chromedriver.exe")
  #maximize the browser window
  driver.maximize_window()
  #open the url in the browser
  driver.get("https://www.mirrorfiction.com/zh-Hant/book/406")
  #click on the first menu item 小說
  driver.find_element_by_xpath("//nav[@id='nav']/div/ul/li/a/span[@class='text novel']").click()
  

来源：https://stackoverflow.com/questions/44224924/how-to-test-non-standard-drop-down-lists-through-a-crawler-using-selenium-and-py