Unique things about arguments in functions in Javascript:
1) You can pass any number of parameters to a function without causing an error.
2) You can also pass in no arguments but still make use of arguments inside the function (through arguments array)
3) you have access to arguments[0], arguments[1] etc in a function
4) arguments.length will give you number of parameters passed in. This is the way you can achieve function overloading. Based on number of parameters you do one thing or the other.
5) If you define multiple functions with same name, the one which is defined last will override all others.