Playing with Javascript

Today class, it was kind of fun for me. Recalling the memory of Javascript. +, -, => <-these stuff. I've been using these for QBasic ages ago. haha. and also some of Javascript. Playing with function script is quite interesting.
But the fact is that giving this function in the html have been changed quite much to what I've leant before. Hmm...yeah, it's difficult. But it is good opportunity to refresh and update my old knowledge. XD