window.open() works first time only in Windows Phone 8

I am developing an HTML5 app with Intel SDK, compiling for Windows Phone 8 platform, and deploying and testing on Nokia Lumia 530.

Inside my app, an internal button must open an URL in system browser:

HTML: <button class = "ui-btn my-button" id = "testExternalLink1"> Button 1 </ button>

JS: $ ("# testExternalLink1"). On ('click', function () {window.open ('http://www.google.it', '_system');});

The workflow works perfectly the first time (when I click the button, system opens the browser with correct URL), but if I go back from browser (with system back button) and I press the same button again I have no feedback. The browser is called only the first time.

In summary: window.open() works first time only in Windows Phone 8.

Someone can give me help?