CSS下拉菜單箭頭怎么寫

在CSS中，我們可以通過添加一些樣式來創(chuàng)建下拉菜單的箭頭，這通常涉及到使用偽元素（如::after）來在菜單項(xiàng)后面添加一個小箭頭，以下是一個基本的示例：

1、我們需要創(chuàng)建一個基本的下拉菜單結(jié)構(gòu)，這可以通過HTML的select元素或div元素來實(shí)現(xiàn)。

<div class="dropdown">
    <div class="dropdown-item">菜單項(xiàng)1</div>
    <div class="dropdown-item">菜單項(xiàng)2</div>
    <div class="dropdown-item">菜單項(xiàng)3</div>
    <div class="dropdown-item">菜單項(xiàng)4</div>
    <div class="dropdown-item">菜單項(xiàng)5</div>
    <div class="dropdown-item">菜單項(xiàng)6</div>
    <div class="dropdown-item">菜單項(xiàng)7</div>
    <div class="dropdown-item">菜單項(xiàng)8</div>
    <div class="dropdown-item">菜單項(xiàng)9</div>
    <div class="dropdown-item">菜單項(xiàng)10</div>
    <div class="dropdown-item">菜單項(xiàng)11</div>
    <div class="dropdown-item">菜單項(xiàng)12</div>
    <div class="dropdown-item">菜單項(xiàng)13</div>
    <div class="dropdown-item">菜單項(xiàng)14</div>
    <div class="dropdown-item">菜單項(xiàng)15</div>
    <div class="dropdown-item">菜單項(xiàng)16</div>
    <div class="dropdown-item">菜單項(xiàng)17</div>
    <div class="dropdown-item">菜單項(xiàng)18</div>
    <div class="dropdown-item">菜單項(xiàng)19</div>
    <div class="dropdown-item">菜單項(xiàng)20</div>
    <div class="dropdown-item">菜單項(xiàng)21</div>
    <div class="dropdown-item">菜單項(xiàng)22</div>
    <div class="dropdown-item">菜單項(xiàng)23</div>
    <div class="dropdown-item">菜單項(xiàng)24</div>
    <div class="dropdown-item">菜單項(xiàng)25</div>
    <div class="dropdown-item">菜單項(xiàng)26</div>
    <div class="dropdown-item">菜單項(xiàng)27</div>
    <div class="dropdown-item">菜單項(xiàng)28</div>
    <div class="dropdown-item">菜單項(xiàng)29</div>
    <div class="dropdown-item">菜單項(xiàng)30</div>
    <div class="dropdown-item">菜單項(xiàng)31</div>
    <div class="dropdown-item">菜單項(xiàng)32</div>
    <div class="dropdown-item">菜單項(xiàng)33</div>
    <div class="dropdown-item">菜單項(xiàng)34</div>
    <div class="dropdown-item">菜單項(xiàng)35</div>
    <div class="dropdown-item">菜單項(xiàng)36</div>
    <div class="dropdown-item">菜單項(xiàng)37</div>
    <div class="dropdown-item">菜單項(xiàng)38</div>
    <div class="dropdown-item">菜單項(xiàng)39</div>
    <div class="dropdown-item">菜單項(xiàng)40</div>
    <div class="dropdown-item">菜單項(xiàng)41</div>
    <div class="dropdown-item">菜單項(xiàng)42</div>
    <div class="dropdown-item">菜單項(xiàng)43</div>
    <div class="dropdown-item">菜單項(xiàng)44</div>
    <div class="dropdown-item">菜單項(xiàng)45</div>
    <div class="dropdown-item">菜單項(xiàng)46</div>
    <div class="dropdown-item">菜單項(xiàng)47</div>
    <div class="dropdown-item">菜單項(xiàng)48</div>
    <div class="dropdown-item">菜單項(xiàng)49</div>
    <div class="dropdown-item">菜單項(xiàng)50</div>
    <input type="text" id="search" placeholder="搜索...">
    <button id="search_button" onclick="search()">搜索按鈕</button>
    <a href="#" id="reset_search" onclick="resetSearch()">重置搜索按鈕</a>
}