How to Convert Decimal to Hexadecimal in JavaScript

How to convert decimal to hexadecimal in JavaScript

Convert a number to a hexadecimal string with:

hexString = yourNumber.toString(16);

And reverse the process with:

yourNumber = parseInt(hexString, 16);

How to convert Decimal to Hexadecimal in JavaScript?

You actually need to parse the prompt in integer :

var decimal = parseInt(prompt("Write your decimal number"));

var hex = decimal.toString(16);
alert(hex);

https://jsfiddle.net/rvzayaph/6/

JavaScript convert long decimal to hex and back

You are beyond the limits of JavaScript maximum. Use BigInt instead.

BigInt("72058145430680163").toString('16'); // Returns 10000806191b263 as String

And this does the whole round trip

BigInt("0x" + BigInt("72058145430680163").toString('16')).toString() // Retuns 72058145430680163

More information on BigInt here:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt

How do you convert a hexadecimal of type string to number in JS?

You can use the Number function, which parses a string into a number according to a certain format.

console.log(Number("0xdc"));

How would I use js to convert a decimal to number to a hex string?

76561198291043943 is greater than Number.MAX_SAFE_INTEGER.

Use BigInt instead:

console.log(BigInt("76561198291043943").toString(16))

Javascript convert decimal to hexadecimal

This Function lets u change your decimal to any new base between 2 and 36.

For Example 255 and 16 would return FF

fromDecToBase:function(int, toNewBase) {
    var letters = ["0","1","2","3","4","5","6","7","8","9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
    var returnValue= "";
    if (toNewBase > 1 && toNewBase < 37) {
        while(int != 0) {
            rest = int % toNewBase;
            int = Math.floor(int / toNewBase);
            returnValue= letters[rest] + returnValue;
        }
    }
    return returnValue;
},

All u need to do after it is check whether the string is 2 letters long or not which could be done the following way:

toHex:function(int) 
{
    hex = fromDecToBase(int, 16);
    return hex.length == 1 ? "0"+hex:hex;
},

How to convert a decimal number in a hexadecimal number in JavaScript?

Javascript numbers are IEEE double-precision floats. The set of integers that can be represented exactly are those integers n such that - 2⁵³-1 <= n <= 2⁵³-1.

The constant Number.MAX_SAFE_INTEGER has the value 2⁵³-1, or 9,007,199,254,740,991 decimal.

Your value 76,561,199,121,591,748 is an order of magnitude larger than Number.MAX_SAFE_INTEGER and so can't be represented exactly.

You might take a look at using BigInt instead of Number.

Build Decimal to Hexadecimal converter without the toString() JavaScript method

Your hexa object keys and values should be reversed since you are looking for numbers to map to a character.

var hexa = { 10: 'A', 11: 'B', 12: 'C', 13: 'D', 14: 'E', 15: 'F' };

Then you can use Map() to do the transformation.

result = result.map(value => value >= 10 ? hexa[value] : value);

To convert this result to hexadecimal number you can use Array.join() with empty character as the separator.

var hex = result.join('');

Live Example:

var hexa = { 10: 'A', 11: 'B', 12: 'C', 13: 'D', 14: 'E', 15: 'F' };

var valor = 127;

var result = [];

while (valor > 0) {

  result.push(valor % 16);

  valor = Math.floor(valor / 16);

}

result = result.reverse();

result = result.map(value => value >= 10 ? hexa[value] : value);

console.log(result);

var hex = result.join('');

console.log("Hexadecimal number: " + hex);