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You've seen brief glimpses of them before in the earlier lessons, they're variables and they're used

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all over the place in programming, they're one of the four core fundamentals of any programming, language

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and a variable.

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What it is, is it's allows you to hold information in a value.

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So if you're typing out a really long paragraph, like I really, really enjoy working with JavaScript

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and you want to have that message and maybe even update that message, well, the best place to place

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it is within a variable.

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And then you can reference it just by using variable message and then you can always get that information

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back in.

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Variables are assigned so they can assign values to them by using the equal sign.

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So variables when we are trying to use them, you need to declare them as well.

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And in order to declare a variable, that's where that var came in.

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And we did see this earlier where we were declaring variables of A, B, C and so on.

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So we're using variable X to equal one.

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So they could be numbers, they can be strings.

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And there's more on this coming up in the upcoming lessons.

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So for now we can see that we've got a variable we can console logout its value.

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So referencing the variable by the name.

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So if we want to set a variable X to equal one, then we can use console log and return back that variable

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value just by referencing X.

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And then we can also update the value that's contained for X and we can set it to two or whatever value

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we want.

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And in JavaScript it's dynamic typing so we can switch between different types so we can have numbers

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and strings.

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And of course, more on this later on in the lesson.

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So there's a quick challenge for you in this lesson and that's to declare a variable.

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You can use a simple variable name such as ABCDE e whatever you want, and then or you could call it

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message and then update that value to a new message and then also declare a variable that holds your

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name and then change it to your friend's name and output it in the console.

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So that's the challenge.

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And there's a code snippet to go along with this.

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So you can see that we're first starting out by console, logging out the value of a as so setting it

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as hello world and logging it out.

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And then we've got welcome back and we're logging out that variable of eight again and we're going to

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see it's got a different message and then we're setting a name and we're console logging out the name

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and then we're setting the name of our friend and we're console logging out that name.

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So let's try that out so we can pause the video here and write the code opening brackets.

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First, we're going to declare a variable.

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So we're going to just use a as a basic variable.

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And there are some rules which we are going to be covering later on.

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So setting the variable value of a two hello world.

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And now if I go into the console, if I type out A, I can see how the world gets returned back.

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And if I want to see it directly within the console without having to type A, I can console log that.

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And when I refresh, I see how the world is written in my console.

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So the objective of this lesson was also to assign a new value to a.

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So once I've declared a I don't have to redeclared again.

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So I'm not using VAR again because that information is contained already within the variable of a so

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I don't have to declare it again, but I can reassign values with the equals sign.

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So this is just that one equals sign and we want it to write in a usage of welcome back to that value

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of eight and then logging out the console message one more time.

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So now you can see that initially when we come in, the value of a hello world and then next time we

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output the value of a it's changed to welcome back.

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And there is a second part to this challenge that was to create a name.

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So giving your name within the variable value and console, logging out that my name variable and then

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taking the my name variable and assigning a new value to it.

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So in this case, I'm going to sign it to John and then once again console logging out my name variable

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and seeing the changes.

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So you can see that we were able to declare the variable with the value, assigning a value to it as

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we declared it.

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And then we updated the value and we have different values coming back in the output.

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So coming up next, there is a little bit more information on variable, so we need to cover.

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That's still to come.