Language Details: Javascript

JavaScript is a prototype-based scripting language that is dynamic, weakly typed, and has first-class functions.

JavaScript article on Wikipedia
Code Jam 2012 Contestants using Javascript
Qualification Round
Used in 264 solutions by 102 contestants:
Round 1A
Used in 24 solutions by 14 contestants:
Round 1B
Used in 11 solutions by 6 contestants:
Round 1C
Used in 19 solutions by 11 contestants:
Round 2
Used in 4 solutions by 3 contestants:

Submission Origin

United States (18 contestants)
China (8 contestants)
Canada (7 contestants)
Spain (7 contestants)
Australia (6 contestants)
Japan (6 contestants)
Brazil (5 contestants)
Netherlands (3 contestants)
Taiwan (3 contestants)
Thailand (3 contestants)
Colombia (2 contestants)
France (2 contestants)
Hong Kong (2 contestants)
India (2 contestants)
Mexico (2 contestants)
Singapore (2 contestants)
Sweden (2 contestants)
United Kingdom (2 contestants)
Argentina (1 contestant)
Austria (1 contestant)
Chile (1 contestant)
Czech Republic (1 contestant)
Germany (1 contestant)
Hungary (1 contestant)
Iceland (1 contestant)
Israel (1 contestant)
Italy (1 contestant)
Latvia (1 contestant)
Malaysia (1 contestant)
Morocco (1 contestant)
New Zealand (1 contestant)
Portugal (1 contestant)
Romania (1 contestant)
Russia (1 contestant)
Saint Kitts and Nevis (1 contestant)
Serbia (1 contestant)
South Korea (1 contestant)
Turkey (1 contestant)
Ukraine (1 contestant)
Venezuela (1 contestant)
Vietnam (1 contestant)