> Having a working knowledge of C won't kill you.
I do have some knowledge of C, and I could learn more. But unless I change career, I'll always be faster and more effective in JavaScript because I think in it all day, so I'll almost always choose JS over C. I'm not disparaging anyone who uses C, just answering @faaef's question about why people "feel the need" to make everything in JavaScript – because they can, they happen to know JS very well, and because there's automatically a huge potential contributor base.
> could you explain how JS is the most widely used language in the world?
I don't know, but I assumed it's the most widely used because websites :) Also it's the most popular language on GitHub