Untitled

<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<div id="result"></div>
<div id="time"></div>

<script type="text/javascript">
let performanceBeginning = performance.now();


let startPoint   = 10000,
    endPoint     = 100000,
    primeNumbers = [],
    palindromes  = [];

var palarray = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

primeNumbers = calcPrimeNumbers(startPoint, endPoint);
let perfPrimes = performance.now();
palindromes  = multiplyNumbers(primeNumbers);

showResult(palindromes);

// find all prime numbers in provided segment
function calcPrimeNumbers(startPoint, endPoint) {
  let array = [];

  // we wanna do += 2
  array.push(2);
  // test i for being prime
  for (let i = 3; i < endPoint; i+=2) {
      // loop through found primes
      let isPrime = true;
      for (let j = 0; (j < array.length) && (array[j]*array[j] < i); j++) {
          // check if divisor
          if ( i % array[j] == 0) {
              isPrime = false;
              break;
          }
      }
      if (isPrime)
          array.push(i);
  }

  return array;
}

// multiply all numbers in array with themselves and return the biggest number
function multiplyNumbers(array) {

  // loop through all values in array
    // "i" variable is an index of the current multiplicand in array
    let ist = 0;
    let jst = 0;
    let biggestPalindrome = 0;
    for (let i = 0; i < array.length; i++) {
        // loop through the rest of array values
        for (let j = i + 1; j < array.length; j++) {

            let product = array[i] * array[j];

            // check if product is palindrome and bigger than previous biggest number
            if (product > biggestPalindrome && isPalindrome(product)) {
                ist = i;
                jst = j;
                biggestPalindrome = product;
            }
        }
    }

    return {
        multiplier: array[ist],
        multiplicand: array[jst],
        product: biggestPalindrome
    };
}


function isPalindrome(number) {
    let i = 0;
    for (i = 0; number > 0; i++)
    {
        palarray[i] = number % 10;
        number = ~~(number/10);
    }
    for (let j = i >> 1; j >=0; j--)
    {
        if (palarray[j] != palarray[i - j - 1])
            return false;
    }
    return true;
}

function showResult(result) {
  let string = JSON.stringify(result);
  let div = document.getElementById('result');

  div.innerHTML = string;
}

let performanceEnd = performance.now();
document.getElementById('time').innerHTML = 'Script has been executed in ' + ((performanceEnd - performanceBeginning) / 1000)
    + ' seconds primes in ' + ((perfPrimes - performanceBeginning) / 1000);

</script>


</body>
</html>