Introduction Javascript Math Floor() Function with Examples

In JavaScript, floor() is a function that is used to return the largest integer value that is less than or equal to a number. In other words, the floor() function rounds a number down and returns an integer value. Because the floor() function is a static function of the Math object, it must be invoked through the placeholder object called Math.

Syntax

In JavaScript, the syntax for the floor() function is:

Math.floor(x)

Parameter(s)

• x - The number used to find the largest integer value.

Return value

The floor() function returns the largest integer value that is less than or equal to a number.

Note

• If no argument is passed, this method returns negative NaN.
• If any of the arguments cannot be converted into a valid number, this method returns NaN.
• If a parameter is null, this method returns 0.
• If a parameter is an empty string, this method returns 0.
• If a parameter is an empty array, this method returns 0.
• This method returns the same value for Math.ceil(x) and -Math.floor(-x).

Browser Support:

• Google Chrome v1
• Internet Explorer v3
• Firefox v1
• Edge v12
• Opera
• Safari v1
• Android webview v1
• Chrome for Android v18
• Firefox for Android v4
• Opera for Android
• Safari on iOS v1
• Samsung Internet v1.0
• Node.js

Javascript Math Floor() Method with Example

Example 1

console.log(Math.floor(32.65));
console.log(Math.floor(8.1));
console.log(Math.floor(-4.2));

Output

32
8
-5

In this example, the first output to the console log returned 32 which is 32.65 rounded down to an integer value.

The second output to the console log returned 8 which is 8.1 rounded down to an integer value.

The third output to the console log returned -5 which is -4.2 rounded down to an integer value. Notice that when dealing with negative numbers, the floor() function rounds away from zero and in this case, returned -5 and not -4.

Example 2

The following example demonstrates the case no argument is passed.

console.log(Math.floor());

Output

NaN

Example 3

The following example demonstrates the cases where 0 is returned.

var a = null;
var b = "";
var c = [];

console.log(Math.floor(a));
console.log(Math.floor(b));
console.log(Math.floor(c));

Output

0
0
0

Example 4

The following example demonstrates the cases where NaN is returned and cases where it can be avoided.

var a = "JavaScript"; 	   // non-numeric string
var b = [1, 2, 3, 4];      // array with more than one element
var c;		           // undefined variable
var d = {};                // empty object

console.log(Math.floor(a));
console.log(Math.floor(b));
console.log(Math.floor(c));
console.log(Math.floor(d));

var e = "23.5";  		//numeric string
var f = [10.2]; 		//array with a single element

console.log(Math.floor(e));
console.log(Math.floor(f));

Output

NaN
NaN
NaN
NaN
23
10

Example 5

The following example demonstrates that Math.ceil(x) returns same value as -Math.floor(-x).

var x = 45.6;

console.log(Math.ceil(x));
console.log(-Math.floor(-x));

Output

46
46

Thanks for reading !

#js #javascript