javascript window.location in new tab
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 :)
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.
You can even use
window.open('https://support.wwf.org.uk', "_blank") || window.location.replace('https://support.wwf.org.uk');This will open it on the same tab if the pop-up is blocked.