JavaScript
Operators
JavaScript
Comparison Operators
Operator Description
== equal to
=== equal value and equal type
!= not equal
!== not equal value or not equal type
> greater than
< less than
>= greater than or equal to
<= less than or equal to
? ternary operator
Comparison
operators are fully described in the JS Comparisons chapter.
Example
Assign
values to variables and add them together:
var
x = 5; // assign the value 5 to x
var
y = 2; // assign the value 2 to y
var
z = x + y; // assign the value 7 to z
(x + y)
»
The
assignment operator (=) assigns a value to a variable.
Assignment
var x = 10;
»
The addition
operator (+) adds numbers:
Adding
var
x = 5;
var
y = 2;
var
z = x + y;
»
The
multiplication operator (*) multiplies numbers.
Multiplying
var
x = 5;
var
y = 2;
var
z = x * y;
»
JavaScript
Arithmetic Operators
Arithmetic
operators are used to perform arithmetic on numbers:
Operator Description
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulus
++ Increment
-- Decrement
Operator Example Same
As
= x = y x
= y
+= x += y x
= x + y
-= x -= y x
= x - y
*= x *= y x
= x * y
/= x /= y x
= x / y
%= x %= y x
= x % y
The addition
assignment operator (+=) adds a value to a variable.
Assignment
var
x = 10;
x
+= 5;
»
Assignment
operators are fully described in the JS Assignment chapter.
JavaScript
String Operators
The +
operator can also be used to add (concatenate) strings.
Example
txt1
= "John";
txt2
= "Doe";
txt3
= txt1 + " " + txt2;
The
result of txt3 will be:
John Doe
»
The +=
assignment operator can also be used to add (concatenate) strings:
Example
txt1
= "What a very ";
txt1
+= "nice day";
The result
of txt1 will be:
What a very
nice day
»
When used on
strings, the + operator is called the concatenation operator.
Adding
Strings and Numbers
Adding two
numbers, will return the sum, but adding a number and a string will return a
string:
Example
x
= 5 + 5;
y
= "5" + 5;
z
= "Hello" + 5;
The
result of x, y, and z will be:
10
55
Hello5
»
If you add a
number and a string, the result will be a string!
JavaScript
Logical Operators
Operator Description
&& logical and
|| logical or
! logical not
Logical
operators are fully described in the JS Comparisons chapter.
JavaScript
Type Operators
Operator Description
Type of Returns the type of a variable
instance of Returns true if an object is an instance of
an object type
Type
operators are fully described in the JS Type Conversion chapter.
JavaScript
Bitwise Operators
Bit
operators work on 32 bits numbers.
Any numeric
operand in the operation is converted into a 32 bit number. The result is
converted back to a JavaScript number.
Operator Description Example Same as Result Decimal
& AND 5
& 1 0101 & 0001 0001
1
| OR 5 |
1 0101 | 0001 0101 5
~ NOT ~
5 ~0101 1010 10
^ XOR 5
^ 1 0101 ^ 0001 0100 4
<< Zero fill left shift 5 << 1 0101 <<
1 1010
10
>> Signed right shift 5 >> 1 0101 >>
1 0010 2
>>> Zero fill right shift 5 >>> 1 0101 >>> 1 0010 2
The examples
above uses 4 bits unsigned examples. But JavaScript uses 32-bit signed numbers.
Because of
this, in JavaScript, ~ 5 will not return 10. It will return -6.
~00000000000000000000000000000101
will return 11111111111111111111111111111010
0 comments: