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Welcome.

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In this lecture, we're going to explore the difference between server scripts and local scripts.

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As many beginners get lost when to use these two different scripts, what's important to understand

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is that Roblox is an online game.

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Meaning whenever you join an experience, you download a copy of that game onto your computer, meaning

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you download all the audio, the parts, the scripts, and so on.

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Your computer is rendering a copy of the game that is separate from the server.

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Whenever the server makes changes to the game, the server tells you to do that as well on your copy,

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the server or server scripts, which I'll create real quick here in the workspace.

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These scripts make changes to the game that all players can see.

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This can be things such as updating leaderboards, spawning in NPCs, changing maps, giving players

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tools, and so on.

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The purpose of server scripts is for you to code logic in your game that needs to affect all players.

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There also used to verify information coming from clients through remote events, which we're going

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to talk about more in a future course.

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Most of the time your server scripts are going to be located in the server script service container,

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and this is a special service used for organizing our server scripts.

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No clients or players in our game have access to this service.

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It's reserved only for the server.

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Sometimes you may want to put server scripts inside of the workspace as well, which is fine, but most

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of the time you'll want to put them inside of the server script service.

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We also have the server storage service.

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If we ever need to store any objects in our game that do not need to be replicated to all players.

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The service is also private and can only be accessed by the server.

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Now a local script, which I'll create real quick.

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Here in the workspace, a local script is used for when we want to affect only our copy of the game.

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Local scripts have access to client side features, such as listening to inputs from your mouse and

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keyboard.

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The server is unable to do this because the server is separate from your computer being hosted on a

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computer or somewhere else in the world.

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Therefore, server scripts are unable to listen to inputs from your computer.

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If we wanted to script the functionality for our GUI on our screen, we would have to use a local script

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if we wanted to cause a change in our game's workspace that is only visible on our copy of the game.

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Again, we would have to use a local script if we wanted to manipulate our camera.

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We must use a local script.

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Any changes made with a local script is only visible to our copy of the game, and it does not replicate

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to the server or any other players.

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For a local script to execute, we must place them in a valid container.

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Services.

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These services are either the starter pack, which we use for tools, starter GUI which is used for

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screen GUI, and then inside of starter player.

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We have starter player scripts, which we use for general client side functionality, such as listening

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for when our player dies and displaying a death message in the screen and stuff like that.

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And then we have a starter character scripts, which is used for affecting our player's character,

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like health regeneration.

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When our player's character dies, any character scripts get deleted and a new set of those scripts

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get placed in the player's new character.

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The last container we can place local scripts inside of is going to be replicated first.

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Typically, you only use local scripts in here for loading screens when your player first joins the

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game.

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Otherwise, we don't use replicated first for storing local scripts.

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So if a local script is not stored and these five containers, then they're not going to execute.

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The only exception would be scripts that are stored in a player's character model, but otherwise we

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cannot execute any local scripts that are in, for example, replicated storage.

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We can't execute them if they're in the lighting service or if they're in the workspace.

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It's only within these particular services.

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So to recap, we use server scripts to cause changes that all players can see, and we use local scripts

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to cause changes that only one player can see on their copy of the game.

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So let's go ahead and take a look at the difference between local scripts and server scripts.

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What I'm going to do is I'm going to take this local script that I've created in the workspace, and

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I'm going to change the parent property to be inside of starter player scripts inside of my local script.

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All I'm going to do is create a new variable.

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I'm going to call it part, and I want to create a new part in my game.

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And we can do so using the instance dot new function.

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And then we pass the class name of the new object we would like to create.

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In this case we would like to create a new part.

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From this point we can refer to this part.

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And I want to change the parent of this part equal to the workspace.

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That way it renders on our screen inside of the game.

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And then I also want to make sure that it is anchored.

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So physics are not being applied.

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So we'll set anchor to true.

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And then we're going to change the position of our part.

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Equal to.

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And we're going to use something called a vector three dot new.

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We're going to learn more about vector three later.

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But just for now we've got to pass an x, y and z position so we could set it at like ten, ten and

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ten.

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So now this local script, whenever a player joins our game, we're going to get a copy of this local

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script on our computer.

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And we're going to be executing all of the code inside of this local script.

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And this is going to happen on our copy of the game.

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So we're going to create a new part.

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We're setting the parent of that part equal to the workspace.

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And we're setting it at the position of ten, ten, ten inside of the workspace.

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So if we go ahead and play test our game by hitting play.

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And we try to look for our part.

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There it is.

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We have a new part inside of the workspace, and it has spawned at the position of ten, ten, ten.

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However, if we go ahead and change to the server when we look on the server here, as you can see,

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we cannot see our part anywhere.

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And that's because again, that local script is only affecting our copy of the game.

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The server can't see it, it's only visible on our game right here.

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And that means we can also interact with this part, such as jumping on it.

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So here we are.

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I'm standing on my part, but if I go and look on the server, as you can see, the server can't see

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the part.

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There's nothing here.

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And it just looks like our player's character is floating.

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Now.

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Instead what I'm going to do as I'm going to copy this code.

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And I'm going to delete it out of here and then place it inside of my server script.

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And this is going to do the exact same thing.

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But this time since the server is creating it, it should be visible for my copy of the game and it

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should also be visible on the server as well.

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So if we go ahead and hit play.

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And we go and look around.

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There we are.

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There is our part.

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And if we switch to the view on the server, as you can see, the server can see it as well.

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Now, let's say I had a local script here on the client that went and deleted this part.

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So I'm just going to select it here and I'm just going to delete the part.

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So I'm going to hit delete on my keyboard.

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Now it is gone out of our copy of the game.

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And then if I go back on the server as you can see it's still here.

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Right?

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But on our local copy of the game, we don't see the part anymore because we deleted it.

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And again, this applies for all properties and objects in our game.

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Whenever a server script makes a change to an object or a property, all players in the game will observe

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that change.

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But if a player on their local copy of the game makes a change to an object or a property through a

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local script, it's only going to be visible on that player's copy of the game.

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No other player is going to be able to see it, and the server is not going to be able to see it either.

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And this works, as I said, for all properties.

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So for example, if I were to refer to the workspace and get the spawn location and let's say I wanted

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to change the color to something new, and we do so using a color three dot new.

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Again, we're going to be learning about these data types later.

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But for now I'm just going to change it to let's say we want to change it to a blue color.

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So then we go and playtest our game again.

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As you can see, our spawn location is now blue, but if we go look at the server, it's also blue,

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and then we go back to the client.

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If the client through a script decides to change the color.

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Let's say we change it to green.

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We can see that it's green on our copy of the game, but if we go and look on the server, it is still

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blue.

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All righty.

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I hope that cleared up the differences between local scripts and server scripts.

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That's all for me for this lecture, and I will see you in the next one.