Yii Post request to current page?

Question

Yii

in php constantly used post requests. and in yii even everything goes through controllers, ajax and so on.
how mona implement the following

<form id="newForm"  method="post">
<input type="submit" name="ex" value="Excel" onclick="document.getElementById("newForm").submit()">
  </form>

if(isset($_POST["ex"])) 
    {
      header('Content-Type: text/x-csv; charset=utf-8');
      header("Content-Disposition: attachment;filename=".date("d-m-Y")."-export.xls");
      header("Content-Transfer-Encoding: binary ");
    }

Answer 1

https://github.com/yiisoft/yii2/blob/master/docs/g...
https://github.com/yiisoft/yii2/blob/master/docs/g...
and it might be useful there will be routing
https://github.com/yiisoft/yii2/blob/master/docs/g...