# Functions

* Programs are assigning the values to the memory or variables and running the program to do somethings with the variables.
* without functions programs can't do anything.

Function Expression:

```javascript
var canada = function() {
    console.log("cold");
}
```

Function Declaration:

```javascript
function india() {
    console.log("warm");
}
```

Function Invocation/Call/Execution:

```javascript
canada(); // defined at run time that what this function does
india();  // defined at parse time - hoisting
```

* Function invocation will create an Execution context that gives an this (=window) and arguments object.