How to open external url in system browser

Currently i am opening my website(http://mydomain.com) inside my ionic app

class OpenBrowser{
  constructor(private iab: InAppBrowser) {
    var browser = this.iab.create(url, '_blank', 'location=no,toolbar=no'); 
    browser.on('loadstop').subscribe(res => { });
    browser.on('loadstart').subscribe(res => { 
       if(res.url=='http://outsideurl.com'){
            // ***** If Url Is Out Side App Open In System Browser 
             var _browser = this.iab.create('http://outsideurl.com', '_system', options);
             _browser.show();
       }
    });
  }
}

it is working but while it’s open in system browser it’s also open in inside ionic app

use (url, '_self', 'location=no,toolbar=no');

I am opening my url correctly in inappbrowser when app is launch

var browser = this.iab.create(url, ‘_blank’, ‘location=no,toolbar=no’);

but i want if any extenal url encounter not belongs to my domain then it should be open in system browser

in fact this is also working fine by

var _browser = this.iab.create(‘http://outsideurl.com’, ‘_system’, options);
_browser.show();

new page is load in system browser
**but **
the same page also load inside the app browser as well