If window.open() is used without any parameter than it will open a blank tab. You need to pass url to open a new web page.

 

Please show your code what are the parameters you are passing? If you are using just "window.open()" it will show only blank screen but using "window.open('www.google.com')" will open google in new screen.

 

More about window.open is at:  https://www.w3schools.com/jsref/met_win_open.asp