将值jquery select2传递给控制器

Question

我有这个select2 jQuery模式

 $("select[name='proj_name']").select2({
    ajax: {
      url: '<?php echo base_url(); ?>index.php/Controller_curl?request=projects-search',
      dataType: 'json',
      delay: 500,
      data: function (params) {
        return {
          search: params.term,
          page: params.page || 1
        };
      },
      processResults: function (res, params) {
        var mapped = $.map(res._items, function (obj) {
          return {
            id: obj._id, 
            text: obj.project_name,
            proj_name : obj.project_name
          };
        });
        params.page = params.page || 1;

        return {
          results: mapped,
          pagination: {
            more: (params.page * 25) < mapped.total_count
          }
        };
      },
      cache: true
    },
    placeholder: 'Search for a Project',
  });

我的目标是获取项目名称，然后单击“下载”按钮时将其发送给我的控制器。怎么做？

public function generateXLSX(){
echo $proj_name;
}