如何将下拉菜单与按钮对齐

Question

我有一个带有 html、css 和一些 js 的下拉菜单。它工作正常，我还添加了一些动画。现在我想在点击我按钮下对齐它！我一直在堆栈上环顾四周，尝试使用 float 和 align，但我做不到。抱歉，我是新手，有人可以帮我吗？

感谢任何回复，谢谢。

function myFunction() {
  var x = document.getElementById("Demo");
  if (x.className.indexOf("w3-show") == -1) {
    x.className += " w3-show";
  } else { 
    x.className += " w3-hide";
    setTimeout(function(){
    x.className = x.className.replace(" w3-show", "");
      x.className = x.className.replace(" w3-hide", "");
      
    },500)
  }
}

/*Items menu*/
.user_menu_item {
    display: flex;
    align-items: center;
}

.user_menu_item:hover {
    background: whitesmoke;
    border-left: 4px solid blue;
    transition: 0.3s;
}

.user_menu_item:not(:hover) {
    transition: 0.3s;
}

.user_menu_item > a {
    display: flex;
    align-items: center;
    padding: 12px 10px 12px 10px;
    width: 100%;
    font-size: 14px;
    color: #75777D;
}

.w3-container {
    position: absolute;
    top: 15%;
}

.w3-dropdown-click {
    display: flex;
    position: relative;
}

.w3-dropdown-content {
  display: none;
  background-color: whitesmoke;
  min-width: 160px;
  overflow: hidden;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
  position:relative;
  
  animation:animateFromBottom 0.6s
}

@keyframes animateFromBottom {
    from{bottom:-50px;opacity:0} to{bottom:0;opacity:1}
}

@keyframes animateToBottom {
  from{bottom:0;opacity:1} to{bottom:-50px;opacity:0}
}

.w3-bar-block .w3-bar-item {
    width:100%;
    display:block;
    padding:8px 16px;
    text-align:left;
    border:none;
    white-space:normal;
    float:none;
    outline:0
}

.w3-show-block,.w3-show {
    display:block!important
}

.w3-dropdown-content.w3-hide {
  animation:animateToBottom 0.6s
}

.w3-button {
  float: right;
}

<button onclick="myFunction()" class="w3-button">Click Me!</button> 

<div class="w3-container">
  <div class="w3-dropdown-click">
   
      
   <div id="Demo" class="w3-dropdown-content w3-bar-block w3-border">
    <div class="user_menu_item">
        <a href="/account">
         <span class="link_text">Dashboard</span>
        </a>
    </div>
    
     <div class="user_menu_item">
        <a href="ordini">
         <span class="link_text">I miei ordini</span>
        </a>
    </div>
    
    <div class="user_menu_item">
        <a href="libreria">
         <span class="link_text">Downloads</span>
        </a>
    </div>
    
    <div class="user_menu_item">
        <a href="impostazioni">
         <span class="link_text">Impostazioni</span>
        </a>
    </div>
    
    <div class="user_menu_item">
        <a href="wp-login.php?action=logout">
         <span class="link_text">Logout</span>
        </a>
    </div>
   </div>

  </div>
</div>

Answer 1

您可以创建一个容器 div 来将菜单和按钮本身放入其中，然后像您对菜单所做的那样为该容器提供绝对定位属性。你必须调整你的菜单位置，所以当它出现时它不会与按钮重叠，但我在代码中处理了这一点。此外，如果您希望按钮和菜单位于绝对右侧而不是偏移和溢出屏幕右侧，则需要修改菜单本身的位置。

参见：https://developer.mozilla.org/pt-BR/docs/Web/CSS/position

function myFunction() {
  var x = document.getElementById("Demo");
  if (x.className.indexOf("w3-show") == -1) {
    x.className += " w3-show";
  } else {
    x.className += " w3-hide";
    setTimeout(function() {
      x.className = x.className.replace(" w3-show", "");
      x.className = x.className.replace(" w3-hide", "");

    }, 500)
  }
}

.container {
  display: block;
  margin: 0 0;
  position: absolute;
  top: 10px;
  right: 0px;
}

/*Items menu*/
.user_menu_item {
  display: flex;
  align-items: center;
}

.user_menu_item:hover {
  background: whitesmoke;
  border-left: 4px solid blue;
  transition: 0.3s;
}

.user_menu_item:not(:hover) {
  transition: 0.3s;
}

.user_menu_item>a {
  display: flex;
  align-items: center;
  padding: 12px 10px 12px 10px;
  width: 100%;
  font-size: 14px;
  color: #75777D;
}

.w3-container {
  position: absolute;
  top: 25px;
  right: 0px;
}

.w3-dropdown-click {
  display: flex;
  position: relative;
}

.w3-dropdown-content {
  display: none;
  background-color: whitesmoke;
  min-width: 160px;
  overflow: hidden;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
  position: relative;

  animation: animateFromBottom 0.6s
}

@keyframes animateFromBottom {
  from {
    bottom: -50px;
    opacity: 0
  }

  to {
    bottom: 0;
    opacity: 1
  }
}

@keyframes animateToBottom {
  from {
    bottom: 0;
    opacity: 1
  }

  to {
    bottom: -50px;
    opacity: 0
  }
}

.w3-bar-block .w3-bar-item {
  width: 100%;
  display: block;
  padding: 8px 16px;
  text-align: left;
  border: none;
  white-space: normal;
  float: none;
  outline: 0;
}

.w3-show-block,
.w3-show {
  display: block !important
}

.w3-dropdown-content.w3-hide {
  animation: animateToBottom 0.6s
}

.w3-button {
  display: block;
}

<div class="container">
  <button onclick="myFunction()" class="w3-button">Click Me!</button>

  <div class="w3-container">
    <div class="w3-dropdown-click">


      <div id="Demo" class="w3-dropdown-content w3-bar-block w3-border">
        <div class="user_menu_item">
          <a href="/account">
            <span class="link_text">Dashboard</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="ordini">
            <span class="link_text">I miei ordini</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="libreria">
            <span class="link_text">Downloads</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="impostazioni">
            <span class="link_text">Impostazioni</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="wp-login.php?action=logout">
            <span class="link_text">Logout</span>
          </a>
        </div>
      </div>

    </div>
  </div>
</div>

Answer 2

将popup和button添加到同一个父元素并设置其相对位置，然后将popup值的top值设置为静态值（btn的高度）

function myFunction() {
  var x = document.getElementById("Demo");
  if (x.className.indexOf("w3-show") == -1) {
    x.className += " w3-show";
  } else {
    x.className += " w3-hide";
    setTimeout(function() {
      x.className = x.className.replace(" w3-show", "");
      x.className = x.className.replace(" w3-hide", "");
    }, 500);
  }
}

.main_container {
  position: relative;
}


/*Items menu*/

.user_menu_item {
  display: flex;
  align-items: center;
}

.user_menu_item:hover {
  background: whitesmoke;
  border-left: 4px solid blue;
  transition: 0.3s;
}

.user_menu_item:not(:hover) {
  transition: 0.3s;
}

.user_menu_item>a {
  display: flex;
  align-items: center;
  padding: 12px 10px 12px 10px;
  width: 100%;
  font-size: 14px;
  color: #75777d;
}

.w3-container {
  position: absolute;
  right: 0;
  top: 25px;
}

.w3-dropdown-click {
  display: flex;
  position: relative;
}

.w3-dropdown-content {
  display: none;
  background-color: whitesmoke;
  min-width: 160px;
  overflow: hidden;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
  position: relative;
  animation: animateFromBottom 0.6s;
}

@keyframes animateFromBottom {
  from {
    bottom: -50px;
    opacity: 0;
  }
  to {
    bottom: 0;
    opacity: 1;
  }
}

@keyframes animateToBottom {
  from {
    bottom: 0;
    opacity: 1;
  }
  to {
    bottom: -50px;
    opacity: 0;
  }
}

.w3-bar-block .w3-bar-item {
  width: 100%;
  display: block;
  padding: 8px 16px;
  text-align: left;
  border: none;
  white-space: normal;
  float: none;
  outline: 0;
}

.w3-show-block,
.w3-show {
  display: block !important;
}

.w3-dropdown-content.w3-hide {
  animation: animateToBottom 0.6s;
}

.w3-button {
  float: right;
}

<div class="main_container">
  <button onclick="myFunction()" class="w3-button">Click Me!</button>

  <div class="w3-container">
    <div class="w3-dropdown-click">

      <div id="Demo" class="w3-dropdown-content w3-bar-block w3-border">
        <div class="user_menu_item">
          <a href="/account">
            <span class="link_text">Dashboard</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="ordini">
            <span class="link_text">I miei ordini</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="libreria">
            <span class="link_text">Downloads</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="impostazioni">
            <span class="link_text">Impostazioni</span>
          </a>
        </div>

        <div class="user_menu_item">
          <a href="wp-login.php?action=logout">
            <span class="link_text">Logout</span>
          </a>
        </div>
      </div>

    </div>
  </div>
</div>

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