Conversion from Decimal to octal, binary and hexadecimal in javascript

Question

I have a form where a user enters a decimal number and then from the dropdown menu he chooses if he wants to convert it either to binary, octal or hexadecimal by clicking on a c

Answer 1

Decimal to hex/oct/bin:

const hex = (100).toString(16);     // "64"
const oct = (100).toString(8);      // "144"
const bin = (100).toString(2);      // "1100100"

and same backwards:

const dec0 = parseInt("64", 16);     // 100
const dec1 = parseInt("144", 8);     // 100
const dec2 = parseInt("1100100", 2); // 100