Bootstrap or Zurb Foundation ???
I dont have sufficient information of zurb, so I cannot really say.
Just hearing zub for the first time, but I for sure kno you can't go wrong with Boostrap
Bootstrap is found practically everywhere you find jquery, wordpress, drupal, themeforest, even .NET sef.
Some mobile development frameworks use it as well. It is not that there are no other frontend frameworks mind you.
is themeforest now a front-end language?
No it is not, just a place where you can purchase themes.
The Zurb Foundation framework is alternative to Bootstrap, both came out in the same year (2011), but has a lot of inbuilt components than bootstrap
Interesting, yet I have not happened to troll across it yet. I will investigate this.