bootstrap select多选

1、页面效果

<div class="form-group">
     <div class="col-md-2 control-label"><label>学段:</label></div>
         <div class="col-md-3 controls">
           <select id="period" name="period"  class="selectpicker show-tick form-control" multiple data-live-search="false" >
              <option value="-1">--请选择！--</option>
              <option value="">小学</option>
              <option value="">初中</option>
              <option value="">高中</option>
            </select>
        </div>
    </div>
</div>
2、js

$(window).on('load', function () {
     $('#period').selectpicker({
            'selectedText': 'cat'
     });
});

3、回显值

　　 $('.selectpicker').selectpicker('val', '1,2');