Html-Jquery Sample Code (1)
    
    
      /*html source code --> menu button */
      
  
      <body style="background-color: white;">
      
 <header class="header">
  <h1 class="header-title">content</h1>
  <nav class="header-nav">
   <div class="header-tab">
    <div class="compose">
     <div class="btn">
        <span class="bar1"></span>
        <span class="bar2"></span>
        <span class="bar3"></span>
     </div>
     <div class="menu">
                           
      <ol class="header-menu">
                
        <li><a href="">Top</a></li>
        <li><a href="">List</a></li>
        <li><a href="">Sample</a></li>
        <li><a href="">HTML Sample</a></li>
                            
      </ol>
             
     </div>
    </div>
  
   </div>
  </nav>
 </header>
      
JS Sample Code (2)
    /*JS source code --> menu button */
          
      
$(".btn").on("click", function(){
    $(".btn").toggleClass("close-btn");
    $(".menu").toggleClass("open-menu");
    $(".header-menu").toggleClass("pop-menu");
  });
  
  CSS Sample Code (3)
  
    /*CSS source code --> menu button */
          
  
 
   .pop-menu {
    margin: 0;
    padding: 5px;
    background-color: #5576a3; 
    text-align: left;
    font-weight: normal;
    display: block;
    justify-content: center;
    font-size: 14px;
    line-height: 20px; 
    word-break: normal;
  }