JSFiddle - React, Tailwind, and code Playground

HTML

<SCRIPT SRC="http://eu.static.mega.co.nz/sjcl_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/crypto_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/rsa_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/hex_1.js"></SCRIPT>
<body onload="testcreateHexString();"></body>

JavaScript

function parseHexString(str) { 
    var result = [];
    while (str.length >= 8) { 
        result.push(parseInt(str.substring(0, 8), 16));
		
        str = str.substring(8, str.length);
    }

    return result;
}

function createHexString(arr) {
    var result = "";
    for (var i = 0; i < arr.length; i++) {
        var str = arr[i].toString(16);
		
		z = 8 - str.length + 1;
        str = Array(z).join("0") + str;

        result += str;
    }
	
    return result;
}

function testcreateHexString()
{
   // alert('test function createHexString');
    var key = [16, amit ];
   
    var result = createHexString(key);
    
    //alert ('Hex value:' + result);
    document.writeln('Hex values data :- <br/>' + result);
    
}