You can use this code :
<a href="http://edu.yoursfriends.com/" onclick="window.open('#','_blank');window.open(this.href,'_self');">Open a new tab in background</a>
Here when you will click on this link , this will open a new tab with current page and previous tab will open with new link (edu.yoursfriends.com) .
This will help you, in case any query pls let me know.