# Naming JavaScript Variables
Variable names are known as identifiers in JavaScript.
Ways or styles for naming variables :
-
snake_case :
var my_name = 'Coder Website';
-
camelCase :
var myName = 'Coder Website';
# Rules to create naming a variable in JavaScript
JavaScript has only a few rules to create variable a names.
Variable names must start with a letters (a to z or A to Z), underscore ( _ ), or dollar ( $ ) sign symbols.
After first letter we can use digits ( 0, 1, 2, ... ), For example : data2
Javascript variable are case sensitive, for example a and A. The variable a and A are two different variables name.
# Limitations of variable names
There are few limitations of variable names to creates in JavaScript, Let's see :
variable names must be one or more than one word.
The variable name must contain only letters, digits, or the symbols $ and _.
The first character must not be a digit, begin the name of any variable.
Variable names can not contain any whitespace characters (tabs or spaces).
There are list of several reserved keywords, which cannot be used as the name of a variable, because they are used by the language itself.
For example: let, var, for, while, class, return, and function etc. are reserved.
# Examples to create variable Names ?
create Single variable-name in a line;
➤ Syntax : create variables name;
<script>
var <variable-name>;
let <variable-name>;
const <variable-name>;
</script>
create multiple variables name in a Single Line;
➤ Syntax : create variables name;
<script>
var <variable-name>, <variable-name>, <variable-name>;
let <variable-name>,<variable-name>, <variable-name>;
const <variable-name>, <variable-name>, <variable-name>;
</script>
# Valid or Invalid variables name ?
1.) Valid variable name:
➤ Example : Using var;
<script>
var userName;
var user02;
var _user;
var $user;
</script>
➤ Example : Using let;
<script>
let userName;
let user02;
let _user;
let $user;
</script>
2.) Invalid variable name:
➤ Example : Using var;
<script>
var user-Name; // hyphens '-' aren't allowed in the name
var 2userName;
var @user;
var +user;
</script>
➤ Example : Using let;
<script>
let user-Name; // hyphens '-' aren't allowed in the name
let 2userName;
let @user;
let +user;
</script>
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