# JavaScript | toExponential() Function

The toExponential() method in JavaScript is used to convert a number to its exponential form. It returns a string representing the Number object in exponential notation.

Syntax:

`number.toExponential(value)`

The toExponential() function is used with a number as shown in above syntax using the ‘.’ operator. This function will convert a number to its exponential form.

Parameters: This function accepts a single parameter value . It is an optional parameter and it represents the value specifying the number of digits after the decimal point.

Return Value: The toExponential() method in JavaScript returns a string representing the given number in exponential notation with one digit before the decimal point.

Below examples illustrates the working of toExponential() function in JavaScript:

1. Passing a number as an argument in the toExponential() method. If a number is passed as argument to the toExponential() function then it represents the number of digits after decimal point.
 `       `  `<``script` `type``=``"text/javascript"``> ` `    ``var num = 2.13456; ` `    ``document.write(num.toExponential(2));           ` ` `

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Output:

`2.13e+0`
2. Passing no parameter in the toExponential() method. Below program illustrates this:
 `       `  `<``script` `type``=``"text/javascript"``> ` `    ``var num = 2.13456; ` `    ``document.write(num.toExponential());           ` ` `

Output:

`2.13456e+0`
3. Passing a value which has more than 1 digit before the decimal point in the toExponential() method. Below program illustrates this:
 `       `  `<``script` `type``=``"text/javascript"``> ` `    ``var num=212.13456; ` `    ``document.write(num.toExponential());           ` ` `

Output:

`2.1213456e+2`
4. Passing zero as a parameter in the toExponential() method. Below program illustrates this:
 `       `  `<``script` `type``=``"text/javascript"``> ` `    ``var num = 212.13456; ` `    ``document.write(num.toExponential(0));           ` ` `

Output:

`Output :2e+2`

Exceptions:

1. Range Error: This exception is thrown when the value parameter passed is too small or too large. Values between 0 and 20, inclusive, will not cause a RangeError. If you want to pass larger or smaller values than specified by this range then you have to accordingly implement the toExponential() function.
2. Type Error: This exception is thrown when the toFixed() method is invoked on an object that is not of type number.