This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
In order to restrict browser dependant coding...you can use framework like JQuery...which will take care of the same operation with different browsers with different coding. Thus your app remains browser independant. JQuery has support for Ajax, css