Example
Assign values to variables and add them together:
var y = 2; // assign the value 2 to y
var z = x + y; // assign the value 7 to z (x + y)
|
<!DOCTYPE html> <h1>JavaScript Operators</h1> <p>x = 5, y = 2, calculate z = x + y, and display z:</p> <p id="demo"></p> <script> </body> |
JavaScript Arithmetic Operators
Arithmetic operators are used to perform arithmetic on numbers (literals or variables).
| Operator | Description |
|---|---|
| + | Addition |
| - | Subtraction |
| * | Multiplication |
| / | Division |
| % | Modulus |
| ++ | Increment |
| -- | Decrement |
The addition operator (+) adds numbers:
Adding
var y = 2;
var z = x + y;
|
<script> |
The multiplication operator (*) multiplies numbers.
Multiplying
var y = 2;
var z = x * y;
|
<p id="demo"></p> <script> |
You will learn more about JavaScript operators in the next chapters.
JavaScript Assignment Operators
Assignment operators assign values to JavaScript variables.
| 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 assignment operator (=) assigns a value to a variable.
Assignment
The addition assignment operator (+=) adds a value to a variable.
Assignment
x += 5;
JavaScript String Operators
The + operator can also be used to add (concatenate) strings.
When used on strings, the + operator is called the concatenation operator.
|
<p>The + operator concatenates (adds) strings.</p> <p id="demo"></p> <script> |
The += assignment operator can also be used to add (concatenate) strings:
|
<p>The assignment operator += can concatenate strings.</p> <p id="demo"></p> <script> |
Adding Strings and Numbers
Adding two numbers, will return the sum, but adding a number and a string will return a string:
|
<p>Adding a number and a string, returns a string.</p> <p id="demo"></p> <script> |
The rule is: If you add a number and a string, the result will be a string!
JavaScript Comparison and Logical 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 |
Comparison and logical operators are described in the JS Comparisons chapter.
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| [04] JavaScript Syntax (0) | 2015.07.13 |
| [03] JavaScript Output (0) | 2015.07.13 |