To open all links in new tabs all the time, open a terminal window and type the following command line: "defaults write com.apple.Safari TargetedClicksCreateTabs -bool true" without the quotation ...

Make Firefox automatically switch to newly opened tabs by opening the "Options" window, clicking "Tabs," and then enabling the "When I open a link in a new tab, switch to it immediately" option.

Safari doesn’t have any such setting in its preferences—there is an option to make Command-click open links in new tabs, and that works on links that open new windows.