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We're come to advanced functions.

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The first concept that we would talk about is what we call functions scope, understanding functions.

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Cope will help you to understand when your function works and when it doesn't work, or when your code

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works and when your code doesn't work.

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So let's go start it.

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When we say function, scope or scope for short, it simply means variable and functions visibility.

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Again, in layman's understanding of scope, it simply means that where can I find my variables or where

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can I find my function?

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That I've created that scope for you and we have different types of them, like I said.

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So let's explore more to differentiate between different scope in JavaScript.

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Great.

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So let's say that this is our code that we have written and this code we have a variable being declared

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here and we have an entire function being also declared here and inside my functions we also have some

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variables and if statement be declared inside.

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So for this code, each of these variables and functions has their own scope, meaning where they can

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be found.

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So the first hope is what we call global scope.

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In JavaScript, global scope refers to the root scope of the program, and global scope is a default

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scope for variables and functions defined outside of any other scope.

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This means that variables and functions defined in the global scope are accessible from anywhere in

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the program.

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Again, global scope is also created when your JavaScript code is loaded into the browser and variables

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and functions, is defined in the global scope, are accessible anywhere in your program.

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So this can be very useful when trying to create utility functions or variables that needs to be accessed

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from different parts of the program.

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But however, it can also lead to problems if variables or functions in a global scope are accidentally

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overwritten or modified.

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And we will talk more about this in the upcoming video with code and see the problems about declaring

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variables in a global scope that is scope for you.

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And after that you also have what is called look scope.

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So when you say look at scope, as the name implies, the variables that we declare are locally inside

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the function.

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So the function that we have created has its own scope, meaning that there are so we can have access

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to this variable inside this function scope here called local scope.

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But if I tried to access this particular array outside my function, because this is locally inside

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my function, I cannot access outside the function, meaning the variables are locally hosted inside

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the function.

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That is what you call look scope.

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And apart from that, you also have what is called function scope.

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So what is function scope?

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Well.

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Function scope refers to the visibility of variables within a function.

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Variables that are declared within a function are only accessible within that function.

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This means that if you try to access a variable that is declared inside a function from outside the

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function, you're going to get an error.

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So function scope is very important to understand because it can impact the way your code runs and when

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it doesn't run.

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For example, if you have a variable that is declared inside a function that is, let's say line number

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four, as I said, line number four, let's say count is equal to a R and my array.

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You would not be able to access that function or variable outside the function.

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And I will show you just a second with some code.

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Right.

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So this can be very useful if we want to have a certain piece of code to run under certain conditions.

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However, it can also lead to errors if you are not careful.

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So when we are working with Function's code, it's very important to keep track of your variables and

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where they are declared, and this will help you to avoid error and make your code more clean.

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That is about the function scope.

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And we also have another scope which is called block scope.

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In JavaScript, BlueScope refers to the visibility of variables within a code block.

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So you can see that for this particular function this is our code block because we have for the score

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basis here and here, this is what we call code block.

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A code block is a set of carry braces that encloses one or more statements because now we have what

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is called opening and then closing here and inside is my block scope.

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So if you use if statements and any loop logic like for loop and other loop, we have what is called

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a block scope.

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Great.

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So is declared within a code block are only visible within that block and are not accessible from outside

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the block.

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And one of the most common uses of plus code is with if statement and for loop and other loop as well.

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So the code block associated with an if statement is only executed if the condition evaluates to true,

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this means that variable is declared within the code block will only be accessible within the if statement.

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That is good, right?

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So overall block scope is a way of limiting the visibility of variables to only the code block in which

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they are declared.

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And this can be very helpful in preventing namespace collisions and making code more readable.

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In the next video, let's take these code variables and demonstrate with real code.