If you want to open two webpages or windows at once when someone clicks your link or button so you can promote two offers. Use this script below.
<a href="http://yoursite.com" onclick="location.href='http://yoursite.com;" target="_blank">Open Two Links With One Click</a>
Works great on mobile. when someone clicks they go to the offer you want and another offer opens up behind the webpage without them even knowing. So you make more money.
I could not find the script anywhere on STM. It's probably somewhere. So if you have been looking for it like I have. Here it is.
Simple but effective - nice. AFAIK that should work on all browsers.
This is a superior approach to using window.open() - that function tends to be blocked by ad-blockers, whereas location.href is less likely to be blocked.
Nice
Split test it, don't always expect it to increase ROI... I tested this 18 months ago and got worse results opening offer in new window. After some pondering I came to the conclusion it was a maximum amount of browser windows allowed to be open at once in a mobile browser which stopped the new one opening. Maybe times have changed and mobile browsers are less restrictive on open tabs now - will be interesting to look at. Either way good share! 
I've tested it in all the major mobile browsers and it works perfectly. They don't block it. If you use javascript it will get blocked. This one just opens up one new window and the page they were on just changes to the offer or page you want. I should have been more clear.