I'm trying to open a URL in a new tab, as opposed to a popup window.
I've seen related questions where the responses would look something like:
window.open(url,'_blank');
window.open(url);
Nothing an author can do can choose to open in a new tab instead of a new window; it is a user preference.
CSS3 proposed target-new, but the specification was abandoned.
The reverse is not true; by specifying dimensions for the window in the third argument of window.open(), you can trigger a new window when the preference is for tabs.