make it to decrypt encrypted message by RSA sequence it produces in encryption if you place it back to textarea id=inputMessage and press decrypt. you would need to modify the code to include a decryption algorithm. use the same decryption button for that. output full javascript covered only in <code><pre>.: <code><pre> const maxRange = 5000;
      let n, e, d; // define global variables for encryption and decryption

      // Utility function to check if an input is numeric
      function isNumeric(n) {
        return !isNaN(parseFloat(n)) && isFinite(n);
      }

      const maxSize = 1000; // Max size
      const threshold = 5000; // Threshold value
      let maxRangeInput = document.getElementById("maxRange");
      let warningMsg = document.getElementById("maxRangeWarningMsg");

      // Set initial value
      maxRangeInput.value = maxSize;

      maxRangeInput.onchange = function () {
        let value = maxRangeInput.value;
        if (value > threshold) {
          let confirmation = confirm(
            `!!!WARNING!!! Setting Max Prime Size too large (above ${threshold}) may result in crashes! Do you wish to continue?`
          );

          if (!confirmation) {
            maxRangeInput.value = maxSize; // Reset back to maxSize if declined
            warningMsg.textContent =
              "Max Range reset to safe value: " + maxSize;
          }
        } else {
          warningMsg.textContent = "";
        }
      };

      // Utility function to find the closest prime number
      function isPrime(num) {
        for (let i = 2, max = Math.sqrt(num); i <= max; i++) {
          if (num % i === 0) return false;
        }
        return num > 1;
      }

      function modularExponentiation(base, exponent, modulus) {
        if (modulus === 1n) return 0n;
        let result = 1n;
        for (let i = exponent; i > 0n; i /= 2n) {
          if (i % 2n === 1n) result = (result * base) % modulus;
          base = (base * base) % modulus;
        }
        return result;
      }

      function gcd(a, b) {
        while (b !== 0) {
          let t = a;
          a = b;
          b = t % b;
        }
        return a;
      }

      function closestPrime(num) {
        do num--;
        while (!isPrime(num));
        return num;
      }

      function generatePrimeNumbers() {
        const warningMsg = document.getElementById("warningMsg");
        const pBitSizeElement = document.getElementById("pBitSize");
        const qBitSizeElement = document.getElementById("qBitSize");

        let p = document.getElementById("p").value;
        // Check if input is empty or zero
        if (!isNumeric(p) || p == "" || p == "0") {
          warningMsg.textContent =
            "Invalid input: P should be numeric, not zero and max 5 digits.";
          return;
        }
        p = closestPrime(parseInt(p));

        let q = document.getElementById("q").value;
        // Check if input is empty or zero
        if (!isNumeric(q) || q == "" || q == "0") {
          warningMsg.textContent =
            "Invalid input: Q should be numeric, not zero and max 5 digits.";
          return;
        }
        q = closestPrime(parseInt(q));

        if (!isPrime(p) || p > maxRange) {
          warningMsg.textContent = `${p} is not a valid prime number. Prime numbers within the range should not exceed ${maxRange}.`;
          return;
        }
        if (!isPrime(q) || q > maxRange) {
          warningMsg.textContent = `${q} is not a valid prime number. Prime numbers within the range should not exceed ${maxRange}.`;
          return;
        }

        n = p * q;
        document.getElementById("multiplyPrimes").textContent = n;
        const totient = (p - 1) * (q - 1);

        e = 2;
        while (gcd(e, totient) !== 1) {
          e++;
        }
        document.getElementById("encryptionExponent").textContent = e;

        d = 1;
        while ((e * d) % totient !== 1 || e === d) {
          d++;
        }
        document.getElementById("decryptionExponent").textContent = d;
        document.getElementById("p").value = p;
        document.getElementById("q").value = q;

        // Calculate bit size for P and Q
        const pBitSize = Math.ceil(Math.log2(p + 1));
        const qBitSize = Math.ceil(Math.log2(q + 1));

        pBitSizeElement.innerHTML = `${pBitSize} bits`;
        qBitSizeElement.innerHTML = `${qBitSize} bits`;

        const modulusBitSize = Math.ceil(Math.log2(n + 1));
        document.getElementById("modulusBitSize").innerHTML = `${modulusBitSize} bits`;

        warningMsg.textContent = "";
      }

      document
        .getElementById("generate-primes-btn")
        .addEventListener("click", generatePrimeNumbers);

      // Adapting the Encryption function to handle both ASCII and Numeric encryption.
      document.getElementById("encrypt-btn").addEventListener("click", function () {
        let message = document.getElementById("inputMessage").value;
        let warningMsg = document.getElementById("enwarningMsg");

        // Check if input is empty
        if (message == "") {
          warningMsg.textContent =
            "Invalid input. Please input a message for encryption.";
          return;
        }

        if (document.getElementById("messageMode").value === "numeric") {
          // Numeric encryption, so input must not contain non-numeric characters
          if (!/^\d+$/.test(message)) {
            warningMsg.textContent =
              "Invalid input. Please input numeric characters only.";
            return;
          } else {
            warningMsg.textContent = ""; // Reset any previous warning
            let toEncrypt = BigInt(message);
            message = modularExponentiation(
              toEncrypt,
              BigInt(e),
              BigInt(n)
            ).toString();
          }
        } else {
          // ASCII mode
          message = message
            .split("")
            .map((ch) => {
              let toEncrypt = BigInt(ch.charCodeAt(0));
              return modularExponentiation(
                toEncrypt,
                BigInt(e),
                BigInt(n)
              ).toString();
            })
            .join(" ");
        }
        document.getElementById("encryptionResult").textContent = message;
      });

      // Adapting the Decryption function to handle both ASCII and Numeric decryption.
      document
        .getElementById("decrypt-btn")
        .addEventListener("click", function () {
          let encryptedMessage = document.getElementById("encryptionResult")
            .textContent;
          let decryptedMessage = "";

          if (document.getElementById("messageMode").value === "ascii") {
            decryptedMessage = encryptedMessage
              .split(" ")
              .map((element) =>
                String.fromCharCode(
                  Number(
                    modularExponentiation(
                      BigInt(element),
                      BigInt(d),
                      BigInt(n)
                    )
                  )
                )
              )
              .join("");
          } else {
            // Numeric mode
            decryptedMessage = Number(
              modularExponentiation(BigInt(encryptedMessage), BigInt(d), BigInt(n))
            );
          }
          document.getElementById("decryptionResult").textContent =
            decryptedMessage;
        });

      function generateRandomPrimeNumbers() {
        const warningMsg = document.getElementById("warningMsg");
        const pBitSizeElement = document.getElementById("pBitSize");
        const qBitSizeElement = document.getElementById("qBitSize");

        let p = Math.floor(Math.random() * maxRange) + 1;
        p = closestPrime(p);

        let q = Math.floor(Math.random() * maxRange) + 1;
        q = closestPrime(q);

        // Rest of the code for generating primes, calculating n, e, d is same as for manual generation
        n = p * q;
        document.getElementById("multiplyPrimes").textContent = n;
        const totient = (p - 1) * (q - 1);

        e = 2;
        while (gcd(e, totient) !== 1) {
          e++;
        }
        document.getElementById("encryptionExponent").textContent = e;

        d = 1;
        while ((e * d) % totient !== 1 || e === d) {
          d++;
        }
        document.getElementById("decryptionExponent").textContent = d;
        document.getElementById("p").value = p;
        document.getElementById("q").value = q;

        // Calculate bit size for P and Q
        const pBitSize = Math.ceil(Math.log2(p + 1));
        const qBitSize = Math.ceil(Math.log2(q + 1));

        pBitSizeElement.innerHTML = `${pBitSize} bits`;
        qBitSizeElement.innerHTML = `${qBitSize} bits`;

        const modulusBitSize = Math.ceil(Math.log2(n + 1));
        document.getElementById("modulusBitSize").innerHTML = `${modulusBitSize} bits`;

        warningMsg.textContent = "";
      }

      // Add event listener for "Generate Primes Randomly" button
      document
        .getElementById("generate-primes-random-btn")
        .addEventListener("click", generateRandomPrimeNumbers);
      document.getElementById("maxRange").value = maxSize; </pre></code>