I think the problem is that the syntax looks too much like C and most people assumed they already "knew" Javascript without bothering to learn it from scratch. "Javascript - The Good Parts" should be mandatory reading before touching the language.

At the same time it's a double edged sword - because it looked so similar to C, it most likely was so successful.

I'm talking historically as someone who was the typical C / Perl programmer back in the 90s when the web took off and made this exact mistake.