How to post data to an external webpage using In-app-browser plugin in ionic 4/5?

Is there any way to post a form with some inputs data to an external webpage using In-app-browser plugin in ionic 4/5?

example:

var formData = `<body >
                       <form id="mForm" action="url" method="post">
                          <input type="hidden" name="test" value="123">
                       </form>
               </body>`
var urlContents = "data:text/html;base64,"+ btoa(unescape(encodeURIComponent(formData )));
this.iab.create(urlContents );

The above code is not working.