Weak typing is the Achilles’ Heel of the language for proper software engineering. While it makes writing quick simple scripts for the web browser very easy, it works against you when you’re writing larger applications that require safety and reliability. This is why most major languages are normally strongly typed (not to be confused with statically typed). This is very, very important.
Until then, I strongly suggest that you look to other, much better languages for your IT career, such as Java, Python, Ruby, C++, C# and Scala. Do I know what I’m talking about? Yes, I do.