Basically toFixed ( ) method is used to cut a number after the decimal upto certain point . Suppose i have a number **i.e 12.345678** and i want this number **upto 2 decimal** places only , then using toFixed method i can cut the number after decimal place like **toFixed(2)** result would be **12.34** .
Syntax ->

number.toFixed ( [ fractiondigits ] ) ;

Parameters ->
number -> It is mandatory , and required a Number Object .
fractiondigits -> It is optional . and it return the string whose length is fixed . If fractiondigit is not supply then it return default value i.e zero ( 0 ) .
Example ->

var num = new Number ( 100 ) ;
var fix = num.toFixed ( ) ;
document.write ( fix ) ; //Output -> 100
var num = new Number ( 100.123 ) ;
var fix = num.toFixed ( 4 ) ;
document.write ( fix ) ; //Output -> 100.1230

Error can be of two types in this method i.e
RangeError -> If fractiondigits range is too small or too large . It means its range should be in between 0 to 20 . It allowed to support larger and smaller value as well .
TypeError -> If this method is invoked on an object that is not a Number