Select2：如何获取先前选择的值

Question

我正在使用select v4.0.3。如何获取select元素的替换/上一个值？我已经附加了一个'更改'监听器，但我似乎无法找到以前的值。

Answer 1

可以使用select2:selecting事件

获取以前选择的值

请在此处查看代码：https://codepen.io/jacobgoh101/pen/ZpGvkx?editors=1111

$('select').on('select2:selecting', function (evt) {
  console.log('previously selected ' + $('select').val());
});
$('select').on('select2:select', function (evt) {
  console.log('now selected ' + $('select').val());
});

Answer 2

您可以在选择活动时轻松完成

$(this).on("select2-selecting", function (e) {
    var curentValue = e.val;
    var previousValue = $(this).val();
});

Answer 3

var oldname;//global declaration
$('select').on('select2:selecting', function (evt) {
  oldName= $('select').val();
});
$(select).on("select2:select select2:unselecting", function (e) {
   //For selecting the new option
   var currentName= $(this).select2('data')[0].text;
   console.log(oldName);//you can get old name here also
});