Javascript - Javascript Functions, Passing Parameters, Return Statement, Anonymous, CallBack

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Global and Local Variables in Javascript:
Global Variables − A global variable has a global scope which means it can be defined anywhere in your JavaScript code. Local Variables − A local variable will be visible only within a function where it is defined. Function parameters are always local to that function.

How to Create a Function in Javascript?
A JavaScript function is defined with the function keyword, followed by a name, followed by parentheses (). Function names can contain letters, digits, underscores, and dollar signs (same rules as variables). The parentheses may include parameter names separated by commas: (parameter1, parameter2, )

Function Call and Definition:
Javascript Function call() The JavaScript Function call() method calls a function with a given this value and arguments provided individually. The call() method calls a function by passing this and specified values as arguments.

Passing Parameters to Functions in Javascript:
The parameters, in a function call, are the function's arguments. JavaScript arguments are passed by value: The function only gets to know the values, not the argument's locations.

What is Default Parameters / Arguments in Functions:
In JavaScript, function parameters default to undefined . However, it's often useful to set a different default value.

Return Statement in Javascript:
The return statement ends function execution and specifies a value to be returned to the function caller.

Anonymous Function in Javascript:
In JavaScript, an anonymous function is that type of function that has no name or we can say which is without any name. When we create an anonymous function, it is declared without any identifier. It is the difference between a normal function and an anonymous function.

Callback Function in Javascript:
A callback is a function passed as an argument to another function. This technique allows a function to call another function. A callback function can run after another function has finished.