使用select all将类添加到选中的复选框

Question

我希望在.active为label后.select-input .select-all添加checked类，然后在unchecked时将其删除或其中一个.select-input是unchecked。

为什么不在第一个函数中添加.prop("checked", true)而在第二个函数中触发$("input[name='check']:checkbox").change(function()？

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$(document).ready(function() {
  $(".select-all").on("click", function() {
    $(this).is(":checked") ?
      $(".select-input").prop("checked", true) :
      $(".select-input").prop("checked", false);
  });
});
$("input[name='check']:checkbox").change(function() {
  if ($(this).is(":checked")) {
    $(this)
      .parent("label")
      .addClass("active");
  } else {
    $(this)
      .parent("label")
      .removeClass("active");
  }
});

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.item {
  height: 50px;
  width: 50px;
  border: 3px solid;
  position: relative;
}

.pick-select {
  -webkit-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -o-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -webkit-transform: scale(1);
  -ms-transform: scale(1);
  transform: scale(1);
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 999;
}

.pick-select.active {
  -webkit-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -o-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -webkit-transform: scale(0.8);
  -ms-transform: scale(0.8);
  transform: scale(0.8);
  border: 2px solid red;
}

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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label for="selectall">
<input type="checkbox" id="selectall" class="select-all"/> Select All
</label>
<div class="post-list">
  <div class="item">
    <div>
      <label class="pick-select" for="1"><input id="1" type="checkbox" class="select-input" name="check"></label> 1
    </div>
  </div>
  <div class="item">
    <div>
      <label class="pick-select" for="2"><input id="2" type="checkbox" class="select-input" name="check"></label> 2
    </div>
  </div>
</div>

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Answer 1

更改属性后需要使用.change()：

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$(document).ready(function() {
  $(".select-all").on("click", function() {
    $(this).is(":checked") ?
      $(".select-input").prop("checked", true).change() :
      $(".select-input").prop("checked", false).change();
  });
});
$("input[name='check']:checkbox").change(function() {
  if ($(this).is(":checked")) {
    if($("input[name='check']:checkbox:not(:checked)").length==0){
         $(".select-all").prop("checked", true);
    }
    $(this)
      .parent("label")
      .addClass("active");
      
  } else {
    $(".select-all").prop("checked", false)
    $(this)
      .parent("label")
      .removeClass("active");
  }
});

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.item {
  height: 50px;
  width: 50px;
  border: 3px solid;
  position: relative;
}

.pick-select {
  -webkit-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -o-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -webkit-transform: scale(1);
  -ms-transform: scale(1);
  transform: scale(1);
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 999;
}

.pick-select.active {
  -webkit-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -o-transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  transition: all 600ms cubic-bezier(0.19, 1, 0.22, 1);
  -webkit-transform: scale(0.8);
  -ms-transform: scale(0.8);
  transform: scale(0.8);
  border: 2px solid red;
}

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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label for="selectall">
<input type="checkbox" id="selectall" class="select-all"/> Select All
</label>
<div class="post-list">
  <div class="item">
    <div>
      <label class="pick-select" for="1"><input id="1" type="checkbox" class="select-input" name="check"></label> 1
    </div>
  </div>
  <div class="item">
    <div>
      <label class="pick-select" for="2"><input id="2" type="checkbox" class="select-input" name="check"></label> 2
    </div>
  </div>
</div>

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