― What is Cross-Browser Extension? When you open a site or Blog in your browser (Chrome/Safari/Firefox/Internet Explore), you can see a text line Add This Site To Your Chrome/Safari/Firefox/Internet Explore Browser!. What is this? It is a Add-On for Site or Blog to add a button in your browser. When you click Add button putted after above line. It will automatically add Site or Blog button to your extension bar. When you click this button, you will see all updates of that Site or Blog without open [...].