Window.open not working in geolocation callback

I have a link on the page that should open a new tab and show the driving directions on Google Maps from users location via HTML5 Geolocation to point B. I installed the jsbin of how I was trying to implement this. Here's the link: JSBIN .

I'm guessing this is because I'm trying to call window.open in the callback? If I try the code on the desktop, it tries to open a new window, but I need a new tab. I tried adding "_blank", but that doesn't do the trick ... Also, this should work on a responsive / mobile layout, where the user can run iOS and Mobile Safari, and of course, you can't open the popup ...

Thanks in advance!