what is function, argument and parameters ?

Question

function is a most important of a program

Answer 1

A function is a block of statements that can be used repeatedly in a program.
A function will not execute immediately when a page loads. It will be executed by a call to the function.
A user defined function declaration starts with the word function:

Information can be passed to functions through arguments, which are like variables.
Arguments are specified after the function name, and within the parentheses.
Here, our function takes a number, multiplies it by two, and prints the result:

Default arguments can be defined for the function arguments.
In the example below, we're calling the function setCounter(). There are no arguments, so it will take on the default values that have been defined.