JavaScript: The Definitive Guide, Fourth Edition

Name

Math.ceil( ) — round a number up

Availability

JavaScript 1.0; JScript 1.0; ECMAScript v1

Synopsis

Math.ceil(x)

Arguments

x

Any numeric value or expression.

Returns

The closest integer greater than or equal to x.

Description

Math.ceil( ) computes the ceiling function -- i.e., it returns the closest integer value that is greater than or equal to the function argument. Math.ceil( ) differs from Math.round( ) in that it always rounds up, rather than rounding up or down to the closest integer. Also note that Math.ceil( ) does not round negative numbers to larger negative numbers; it rounds them up toward zero.

Example

a = Math.ceil(1.99);   // Result is 2.0
b = Math.ceil(1.01);   // Result is 2.0
c = Math.ceil(1.0);    // Result is 1.0
d = Math.ceil(-1.99);  // Result is -1.0