Features of javascript:

Some of the features of JavaScript are:
Lightweight
Interpreted programming language
Good for the applications which are network-centric
Complementary to Java
Complementary to HTML
Open source
Cross-platform

Advantages :
Some of the advantages of JavaScript are:

Server interaction is less
Feedback to the visitors is immediate
Interactivity is high
Interfaces are richer

Disadvantages :

Some of the disadvantages of JavaScript are:
No support for multithreading
No support for multiprocessing
Reading and writing of files is not allowed
No support for networking applications.