javascript - 如果选中，则禁用第二个选择框的选项

Question

我有两个选择框，使用 select2 js 插件。两个下拉菜单都有相同的选项。如果在第一个选择框中选择了第二个选择框中选择的选项，我想禁用它，反之亦然。

这是代码:

jQuery(document).ready(function() {
  jQuery('.minimal').select2();
});

<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/css/select2.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/js/select2.min.js"></script>

<select class="minimal" name="coin1">
  <option value="btc">btc</option>
  <option value="usd">usd</option>
  <option value="eth">eth</option>
</select>

<select class="minimal" name="coin2">
  <option value="btc">btc</option>
  <option value="usd">usd</option>
  <option value="eth">eth</option>
</select>

Answer 1

请参阅下面的代码注释:

$(document).ready(function() {
  $('.minimal')
    .select2()
    .change(function() {                      // when changed
      let val = $(this).val();                // save the current value
      $('.minimal').not(this).find('option')  // grab options from other select
        .prop('disabled', function() {        // disable those equal to current value
          return $(this).val() == val;
        })
        .select2();                           // re-establish select2
    });
});

$(document).ready(function() {
  $('.minimal')
    .select2()
    .change(function() {
      let val = $(this).val();
      $('.minimal').not(this).find('option').prop('disabled', function() {
        return $(this).val() == val;
      }).select2();
    });
});

<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/css/select2.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/js/select2.min.js"></script>

<select class="minimal" name="coin1">
  <option value="btc">btc</option>
  <option value="usd">usd</option>
  <option value="eth">eth</option>
</select>

<select class="minimal" name="coin2">
  <option value="btc">btc</option>
  <option value="usd">usd</option>
  <option value="eth">eth</option>
</select>