Get it on http://popunderscript.com/
A smart Popunder script that help you can create popunders on most of browsers, mobile browsers, even on Chrome 43+.
It provides two ways to make pop (under and over) with newTab and blur option.
blur: true, newTab: false for popunder, blur: false for popover. If you using blur: true, newTab: true script will try to make pop on tab-under.
On mobile browsers or Chrome 43, if blur: true, script will not care about newTab option, it will find a best way to make popunder for what browser user using, if it can't make popunder, it will use tab-under to blur.
Script have tested with a lot of browsers and everything is ok, if have any problem just is my english.
Get it on http://popunderscript.com/