切换函数在 transitionend 上触发两次

Question

我有一个开关，我用 jQuery 调用其 checked 状态。每次我单击从未选中切换到选中时，控制台都会记录 "do this!" 两次。为什么此函数会触发两次？让它触发一次的解决方法是什么？

$("#my-toggle").bind("transitionend webkitTransitionEnd oTransitionEnd MSTransitionEnd", function() {
  if (document.getElementById('my-checkbox').checked) {
    console.log("do this!")
  }
});

.switch {
  position: absolute;
  top: 15%;
  display: inline-block;
  width: 60px;
  height: 34px;
}

.switch input {
  display: none;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before,
.slider .number {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider .number {
  background: none;
  font-size: 14px;
  left: 9px;
  top: 9px;
}

input:checked+.slider {
  background-color: #2196F3;
}

input:focus+.slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked+.slider:before,
input:checked+.slider .number {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}


/* Rounded sliders */

.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<label class="switch">
  <input type="checkbox" id="my-checkbox">
  <span class="slider round" id="my-toggle"></span>
</label>

我的最终 HTML 看起来像这样，为此事件触发了三次：

<label class="switch">
  <input type="checkbox" id="my-checkbox">
  <span class="slider round" id="my-toggle">
    <span class="number">00</span>
  </span>
</label>

Answer 1

这来自过渡所关注的元素。如果您放置 console.log(event)（并将其作为事件处理程序的参数），您将看到相关属性为 background-color 和 trandform。这 2 个属性与转换有关，因此每个属性调用一次事件处理程序。

这是 transform "filtering" 上的 "filtering" 片段：

$("#my-toggle").bind("transitionend webkitTransitionEnd oTransitionEnd MSTransitionEnd", function(event){
  if (event.originalEvent.propertyName === "transform" && document.getElementById('my-checkbox').checked){
    console.log("do this!");
  }
 });

.switch {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 34px;
}

.switch input {display:none;}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}

/* Rounded sliders */
.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label class="switch">
  <input type="checkbox" id="my-checkbox">
  <span class="slider round" id="my-toggle"></span>
</label>

Answer 2

有两个 transitionend 事件触发：一个来自您的 #my-toggle <span>，一个来自您的 ::before 伪元素。您需要区分这两个事件。为此，您需要事件参数 e。

唯一的区别是 e.originalEvent.propertyName（对应 CSS 属性）和 e.originalEvent.pseudoElement.

所以让我们检查 if 条件中的最后一个属性。

还要放另一个 && e.target == this 在那里，因为 transitionend event is also firing for children 因为事件冒泡了。由于您只在父级 <span> 上监听事件，您不能简单地调用 e.stopPropagation 这只会用于防止 parent(s) 触发事件。

$("#my-toggle").bind("transitionend webkitTransitionEnd oTransitionEnd MSTransitionEnd", function(e) {
  if (document.getElementById("my-checkbox").checked && !e.originalEvent.pseudoElement && e.target == this) {
    console.log("do this!");
  }
});

.switch {
  position: absolute;
  top: 15%;
  display: inline-block;
  width: 60px;
  height: 34px;
}

.switch input {display:none;}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before,
.slider .number {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}
.slider .number {
  background: none;
  font-size: 14px;
  left: 9px;
    top: 9px;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before,
input:checked + .slider .number {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}

/* Rounded sliders */
.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label class="switch">
  <input type="checkbox" id = "my-checkbox">
  <span class="slider round" id = "my-toggle">
     <span class="number">00</span>
  </span>
</label>

Answer 3

寻找点击功能时使用 .slider 而不是 .switch，这对我有用，我不知道为什么。

$('.slider').on('click',function(){


alert("Test");
});

切换函数在 transitionend 上触发两次

Toggle function fires twice on transitionend

html

javascript

css

jquery

transitionend