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Earlier you learned how to create or
declare variables.

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For example, use the var keyword
followed by a variable name.

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But you can't just use any word for

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a variable name, there are a few
rules you should keep in mind.

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First, JavaScript has a long
list of reserved words.

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These are words that are part of
the JavaScript language itself,

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and are often called keywords.

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Var is an example of a reserved keyword.

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You can't create a variable named var,
for instance.

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In the browser let's
open up the console and

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see what happens if you try to
create a variable named var.

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We get a syntax error, it says
Uncaught SyntaxError Unexpected token var.

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A token is usually one of those
reserved keywords I just talked about.

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This error usually means there's something
in the code that shouldn't be there,

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like an unexpected character.

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And the JavaScript engine doesn't
know what to do with it, like a typo.

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In this case, it's not able to
create a variable name var,

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because var is a reserved word.

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JavaScript has a long list of reserved
words which you will find in the lesson

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with this video, along with the other
rules JavaScript has for naming variables.

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Now don't worry about
memorizing the full list,

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you might even want to bookmark
this page for future reference.