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The toExponential()
method returns a string representing the Number object in exponential notation.
Syntax
numObj.toExponential([fractionDigits])
Parameters
fractionDigits
- Optional. An integer specifying the number of digits after the decimal point. Defaults to as many digits as necessary to specify the number.
Return value
A string representing the given Number
object in exponential notation with one digit before the decimal point, rounded to fractionDigits
digits after the decimal point.
Exceptions
RangeError
- If
fractionDigits
is too small or too large. Values between 0 and 20, inclusive, will not cause aRangeError
. Implementations are allowed to support larger and smaller values as well. TypeError
- If this method is invoked on an object that is not a
Number
.
Description
If the fractionDigits
argument is omitted, the number of digits after the decimal point defaults to the number of digits necessary to represent the value uniquely.
If you use the toExponential()
method for a numeric literal and the numeric literal has no exponent and no decimal point, leave whitespace(s) before the dot that precedes the method call to prevent the dot from being interpreted as a decimal point.
If a number has more digits than requested by the fractionDigits
parameter, the number is rounded to the nearest number represented by fractionDigits
digits. See the discussion of rounding in the description of the toFixed()
method, which also applies to toExponential()
.
Examples
Using toExponential
var numObj = 77.1234; console.log(numObj.toExponential()); // logs 7.71234e+1 console.log(numObj.toExponential(4)); // logs 7.7123e+1 console.log(numObj.toExponential(2)); // logs 7.71e+1 console.log(77.1234.toExponential()); // logs 7.71234e+1 console.log(77 .toExponential()); // logs 7.7e+1
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.5. |
ECMAScript 5.1 (ECMA-262) The definition of 'Number.prototype.toExponential' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Number.prototype.toExponential' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Number.prototype.toExponential' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |