javascript window.location in new tab
Solution 1:
window.open('https://support.wwf.org.uk', '_blank');
The second parameter is what makes it open in a new window. Don't forget to read Jakob Nielsen's informative article :)
Solution 2:
I don't think there's a way to do this, unless you're writing a browser extension. You could try using window.open and hoping that the user has their browser set to open new windows in new tabs.