Basic of JavaScript

Java Script Syntax and Features

 1. There is no need to declare variable, however
you can

     define variable with var keyword.

 2. Curl braces ({}) are separated two code
blocks.

 3. White space and carriage return are not count
in code statement.

 4. Semicolon (;) terminate a statement.

 5. For single line comment use double slash
(//).

 6. For multi line comment use /* and */ sign.

 

Variable name rules

Variable are place holder of value used in run time by the program, every
variable has an unique name within the scope of execution, while declaring the
variable always keep un mind.

 1. Must start with number and underscore (_)

 2. Use any alphanumeric character.

 3. Do not use any special character and white space.

 4. Variable name are case sensitive.

 5. Do not use keyword as variable name.



Operator and order of precedence

1

.

[]

()

2

++

--

!~

3

*

/

%

4

+

-

5

<<

>>

>>>

6

<

>

<=

>=

7

==

!=

8

&

9

^

10

|

11

&&

12

||

13

?:

14

=

+=

-+

*=

/=

%=

<<=

>>=

>>>=

&=

^=

!=

String
Operators

+

Concatenation

Comparison Operators

	==	Equal To
	!=	Not Equal To
	<	Less Than
	>	Greater Than
	>=	Greater than or equal to
	<=	Less than or equal to

Arithmetic Operators

	*	Multiplication
	/	Division
	+	Addition
	-	Subtraction

Logical
Operators

&&

AND

Assignment
Operator

=

Assignment

Keyword List

In
JavaScript there are 50 keywords, this are reserve word in the language you can
not use this keyword in naming of variable or function.

	abstract	float	public
	boolean	for	return
	break	function	short
	byte	goto	static
	case	if	super
	catch	implements	switch
	char	import	synchronized
	class	in	this
	const	instanceof	throw
	continue	int	throws
	default	interface	transient
	do	long	true
	double	native	try
	else	new	var
	extends	null	void
	false	package	while
	final	private	with
	finally	protected

Conditional
Construct

 1. if.. else ..

 2. switch case



Looping Construct

 1. for

 2. while 



User Define Function

 function <functionname>(argument)

 {

   //function body

  return <value>

 }