How to trigger button click located outside an iframe

Communication between two applications, Angular application open ASP.NET web form application inside Kendow window containing iframe.From ASP.NET application want to click the button id=btnClose by Javascript.

 

**Angular form**

Close

 

**ASP.NET Webform**

function FoCloseClcik() {

var win = window.parent.document.getElementById('winID');

var btnClose = window.parent.document.getElementById('btnClose');// Getting conole output as "Close"

}