sent multiple value to innerHTML using javascript

Question

 function showPrimes(n) { for (let i = 2; i < n; i++) { if (!isPrime(i)) continue; console.log(i); // a prime } } function isPrime(n) { for (let i = 2; i < n; i++) { if ( n % i == 0) return false; } return true; } document.getElementById("res").innerHTML = showPrimes(5); 

 <div id='res'></div> 

How to show all showprimes value into the div element it return undefined when using above code

Answer 1

It shows undefined because showPrimes doesn't return anything, so calling it results in the value undefined . If you want it to return something, return something (perhaps an array); then that will get assigned to innerHTML (after being converted to string). See *** comments:

 function showPrimes(n) { const primes = []; // *** for (let i = 2; i < n; i++) { if (!isPrime(i)) continue; console.log(i); primes.push(i); // *** } return primes; // *** } function isPrime(n) { for (let i = 2; i < n; i++) { if ( n % i == 0) return false; } return true; } document.getElementById("res").innerHTML = showPrimes(5); 

 <div id="res"></div> 

That uses the default conversion of array to string, which calls Array#join , which uses a comma between the values. You could call join explicitly to do something else, or any of several other tweaks.

Answer 2

There is small issue in your code:

• You are not returning anything from showPrimes function that can be actually assigned in document.getElementById("res").innerHTML .
• If you directly return a single value from showPrimes function then it will not give you the next prime number as showPrimes function will get terminated. So, the solution would be to store the prime numbers in an array and then return this array when no prime numbers are left to generate.

 var primeArray = []; function showPrimes(n) { for (let i = 2; i < n; i++) { if (!isPrime(i)) continue; console.log(i); // a prime primeArray.push(i); } return primeArray; } function isPrime(n) { for (let i = 2; i < n; i++) { if ( n % i == 0) return false; } return true; } document.getElementById("res").innerHTML = showPrimes(5); 

 <div id='res'></div>