JavaScript String Object JavaScript Number Object

JavaScript toPrecision() Method

toPrecision()The method's purpose is to return a string representing a number with a specified precision.

Syntax:

number.toPrecision(precision)

Example

var num =　5.123456;
num.toPrecision(3);

Test and see‹/›

Browser Compatibility

The toPrecision() method is fully supported by all browsers:

Method
toPrecision()	Is	Is	Is	Is	Is

Parameter Value

Parameter	Description
precision	(Optional) an integer used to specify the number of significant digits

Technical Details

Return value:	a string representing a number formatted to a specified precision
Exception cases:	If the precision is not1to10throws a RangeError if the precision is not between
JavaScript Version:	ECMAScript 3

More Examples

Format a number to a specified length:

Example

var num =　5.123456;
num.toPrecision();//　5.123456
num.toPrecision(1);　　　//　5
num.toPrecision(2);　　　//　5.1
num.toPrecision(3);　　　//　5.12
num.toPrecision(4);　　　//　5.123
num.toPrecision(10);　　//　5.123456000

Test and see‹/›

　JavaScript Number Object