TUTORIALS

THE WORLD'S LARGEST WEB DEVELOPER SITE

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)

Try it Yourself
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:

The multiplication operator (*) multiplies numbers.

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.

The addition assignment operator (+=) adds a value to a variable.

JavaScript String Operators

The + operator can also be used to add (concatenate) strings.

When used on strings, the + operator is called the concatenation operator.

Example

```
txt1 = "John";
```

txt2 = "Doe";

txt3 = txt1 + " " + txt2;

The result of txt3 will be:

```
John Doe
```

Try it Yourself
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
```

Try it Yourself
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

Try it Yourself
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 |

? | ternary operator |

Comparison and logical operators are described in the JS Comparisons chapter.

JavaScript Type Operators

Operator | Description |
---|---|

typeof | Returns the type of a variable |

instanceof | Returns true if an object is an instance of an object type |

Type operators are described in the JS Type Conversion chapter.