Open new window without focus on it [duplicate]

What you seek is called a “pop-under” window

• Open a new window using let handle = window.open()
• Lose focus of the new window by using handle.blur()
• The return focus to your existing window using window.focus()

Example:

var handle = window.open('https://stackoverflow.com/');
handle.blur();
window.focus();

However, it’s not a guarantee as user browser settings may override this behavior, especially pop-up blockers.