JavaScript
variables are containers for storing data values. Variables are containers for
values of all possible types like number, string , array. Every variable gets a
name that can later be used inside your application to read/write its value.
Examples
|
var A =
100;
var name =
"Nitin Kumar";
var
variable1 = 200;
or
var x;
x=100;
|
Steps to
create variable in java script:-
- Declaration
- Initialization
- Assignment
|
Declaration
|
Initialization
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Assignment
|
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The
variable is registered using a given name within the corresponding scope
|
When you
declare a variable it is automatically initialized, which means memory is
allocated for the variable .
|
Here a specific value is assigned to the declared variable.
|
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Warning :
- Variable Name must start with a letter (a to z or A to Z), underscore( _ ),
or dollar( $ ) sign , After first letter we can use digits (0 to 9),and
remember all javascript variables are case sensitive.
|
JavaScript
Variable Scope
JavaScript
variables can have only two scopes.
|
Global Variables
|
Local Variables
|
|
A global
variable has global scope which means it can be defined anywhere in your
code.
|
A local
variable will be visible only within a function where it is defined.
|
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Warning : - JavaScript Reserved Words cannot be used as
JavaScript variables, functions, methods, loop labels, or any object names.
|
Reserved
Words:-
details
of reserved words are given bellow.
|
continue
boolean
break
byte
case
catch
char
class
if
implements
import
do
throws
transient
|
Double
new
null
package
private
protected
public
return
const
finally
debugger
else
enum
export
|
default
delete
float
for
function
goto
typeof
var
void
volatile
while
with
true
try
|
extends
false
final
abstract
instanceof
int
interface
short
static
super
switch
synchronized
this
throw
long
native
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