BsMultiSelect是一款基于Bootstrap 4的多选下拉框插件。该插件能够提供友好的多选功能，并提供一些情节模式和多种主题效果。

使用方法

安装：

npm install @dashboardcode/bsmultiselect

在页面中引入下面的文件。

<!-- Stylesheet -->
<link rel="stylesheet" href="bootstrap.min.css">

<!-- jQuery & Bootstrap -->
<script src="pathto//jquery-3.3.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="bootstrap/4.3.1/js/bootstrap.min.js"></script>
<script src="dist/js/BsMultiSelect.js"></script>
HTML结构
<select name="states" id="example" class="form-control"  multiple="multiple" style="display: none;">
  <option value="AL">Alabama</option>
  <option value="AK">Alaska</option>
  <option value="AZ">Arizona</option>
  <option value="AR">Arkansas</option>
  <option selected value="CA">California</option>
  ...
</select>
初始化插件
$(function(){

  $("select").dashboardCodeBsMultiSelect();

});
配置参数

可用的配置参数的默认值如下：

$("select").bsMultiSelect({
  selectedPanelDefMinHeight: 'calc(2.25rem + 2px)',
  selectedPanelLgMinHeight: 'calc(2.875rem + 2px)',
  selectedPanelSmMinHeight: 'calc(1.8125rem + 2px)',
  selectedPanelDisabledBackgroundColor: '#e9ecef',
  selectedPanelFocusBorderColor: '#80bdff',
  selectedPanelFocusBoxShadow: '0 0 0 0.2rem rgba(0, 123, 255, 0.25)',
  selectedPanelFocusValidBoxShadow: '0 0 0 0.2rem rgba(40, 167, 69, 0.25)',
  selectedPanelFocusInvalidBoxShadow: '0 0 0 0.2rem rgba(220, 53, 69, 0.25)',
  filterInputColor: '#495057',
  selectedItemContentDisabledOpacity: '.65',
  dropdDownLabelDisabledColor: '#6c757d',
  containerClass: 'dashboardcode-bsmultiselect',
  dropDownMenuClass: 'dropdown-menu',
  dropDownItemClass: 'px-2',
  dropDownItemHoverClass: 'text-primary bg-light',
  selectedPanelClass: 'form-control',
  selectedItemClass: 'badge',
  removeSelectedItemButtonClass: 'close',
  filterInputItemClass: '',
  filterInputClass: ''
});

该基于Bootstrap 4的多选下拉框插件的github网址为：https://github.com/DashboardCode/BsMultiSelect