I'm a fairly experienced programmer and JS still drives me up the wall. The implicit casting and inconsistent operator overloads have led to many unhappy visits to Stack Overflow to see just WTF my browser is doing. I can't imagine the experience being any better for newbie programmers! Even simple things, like bitwise operators, are basically broken unless you take care to ensure that your variables are coerced to whole numbers, because all numerics are f%!#^&ing floating point numbers...

Given that the language is such a mess, I think it would induce a new programmer to compartmentalize their JS learnings as a bunch of special case hacks instead of discovering broad language principles that are applied consistently across the language.