141 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| ---
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| title: Dropdowns
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| localeTitle: 下拉菜单
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| ---
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| ## 下拉菜单
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| 
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| 下拉列表在CSS中用于隐藏按钮内的预定义列表。
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| 
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| 例子:
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| 
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| ```html
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| 
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| <div class="dropdown"> 
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|   <button class="dropbtn">Name</button> 
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|   <div class="dropdownContent"> 
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|     <a href="#">One</a> 
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|     <a href="#">Two</a> 
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|     <a href="#">Three</a> 
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|   </div> 
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|  </div> 
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| ```
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| 
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| 然后你应该在CSS中自定义类
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| 
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| ```css
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| .dropdown { 
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|   position: relative; 
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|   display: inline-block; 
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|  } 
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|  
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|  .dropbtn { 
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|   background-color: red; 
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|   padding: 10px; 
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|  } 
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|  
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|  .dropdown-content { 
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|   display: none; 
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|   position: absolute; 
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|  } 
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|  
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|  .dropdown:hover .dropdown-content { 
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|   display:block; 
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|  } 
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| ```
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| 
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| 您需要单独的div类来创建按钮,而另一个div用于分隔按钮所包含的列表。
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| 
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| #### 一个例子
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| 
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| ```html
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| 
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| <div id="container"> 
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|  
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|         <div id="myNav1" class="overlay"> 
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|  
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|             <div class="overlay-content" id="myNav1-content"> 
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|  
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|                 <div> 
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|                     <a href="#" id="list1_obj1" class="list1" >Content 1</a> 
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|                 </div> 
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|                 <div> 
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|                     <a href="#" id="list1_obj2" class="list1" >Content 2</a> 
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|                 </div> 
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|  
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|             </div> 
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|  
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|          </div> 
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|  
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|          <div id="myNav2" class="overlay"> 
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|  
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|              <a href="javascript:void(10)" class="closebtn" onclick="closeNav()">×</a> 
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|             <div class="overlay-content" id="myNav2-content"> 
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|  
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|                 <div> 
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|                     <a href="#" id="list2_obj1" class="list2" >Content 3</a> 
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|                 </div> 
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|                 <div> 
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|                    <a href="#" id="list2_obj2" class="list2" >Content 4</a> 
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|                 </div> 
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|                 <div> 
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|                   <a href="#" id="list2_obj3" class="list2" >Content 5</a> 
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|                 </div> 
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|  
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|             </div> 
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|  
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|          </div> 
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|  
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|  </div> 
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| ```
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| 
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| ```css
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| #myNav1 { 
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|     height: 0; 
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|     width: 50%; 
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|     position: fixed; 
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|     z-index: 6; 
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|     top: 0; 
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|     left: 0; 
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|     background-color: #ffff; 
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|     overflow: hidden; 
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|     transition: 0.3s; 
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|     opacity: 0.85; 
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|  } 
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|  
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|  #myNav2 { 
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|     height: 0; 
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|     width: 50%; 
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|     position: fixed; 
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|     z-index: 6; 
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|     bottom: 0; 
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|     right: 0; 
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|     background-color: #ffff; 
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|     overflow: hidden; 
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|     transition: 0.3s; 
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|     opacity: 0.85; 
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|  } 
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|  
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|  .overlay-content { 
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|     position: relative; 
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|     width: 100%; 
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|     text-align: center; 
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|     margin-top: 30px; 
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|  } 
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|  
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|  #myNav1-content{ 
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|     top: 12%; 
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|     left: 5%; 
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|     display: none; 
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|  } 
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|  
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|  #myNav2-content{ 
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|     top: 12%; 
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|     right: 10%; 
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|     display: none; 
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|  } 
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| ```
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| 
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| #### 更多信息:
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| 
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| *   W3 School Dropdown Hover Button: [链接到W3学校](https://www.w3schools.com/howto/howto_css_dropdown.asp)
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| *   W3学校课程: [连结W3学校](https://www.w3schools.com/css/css_dropdowns.asp) |