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.

javascript - Open a URL in a new tab (and not a new window ...

https://stackoverflow.com/questions/4907843/open-a-url-in-a-new-tab-and-not-a-new-window

open(url, '_blank'); the '_blank' isn't necessary, for window.open(), the second parameter is strWindowName, for: A string name for the new window. The name can ...

Window open() Method

https://www.w3schools.com/jsref/met_win_open.asp

The open() method opens a new browser window, or a new tab, depending on your browser settings and the parameter values. See Also: The close() method. Syntax.

How to open a link in a new tab with HTML and JavaScript

https://www.educative.io/answers/how-to-open-a-link-in-a-new-tab-with-html-and-javascript

To open a URL in a new tab/window in JavaScript, we use the window.open(URL, target) method. To open a new tab, however, we must use _blank as the second ...