<div class="fileButBox">
  <span>批量导入</span>
  <input class="txt_file" type="file" name="file" placeholder="批量导入" data-id="1"/>
</div>

//批量导入用户信息
$(".txt_file").live('change',function(e){

    var fileMsg = e.currentTarget.files[0];//文件数据
    var company_id = $(this).data('id');//其他参数
    //保存
    var formData = new FormData();
    formData.append("file", fileMsg);
    formData.append("id", id);
    
    $.ajax({
        url:'user.php?c=unit_group&a=download_excel', /*接口域名地址*/
        type:'post',
        data: formData,
        contentType: false,
        processData: false,
        success:function(data){
            console.log(data);
        }
    })
});

$file = $_FILES['file'];
$id = $_REQUEST['id'];