JavaScript: Check a number is prime or not

Last update on May 30 2022 10:09:08 (UTC/GMT +8 hours)

JavaScript Function: Exercise-8 with Solution

Write a JavaScript function that accepts a number as a parameter and check the number is prime or not.

Note : A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Pictorial Presentation:

JavaScript: Check a number is prime or not

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Check a number is prime or not</title>
</head>
<body>
 
</body>
</html>

JavaScript Code:

function test_prime(n)
{

  if (n===1)
  {
    return false;
  }
  else if(n === 2)
  {
    return true;
  }else
  {
    for(var x = 2; x < n; x++)
    {
      if(n % x === 0)
      {
        return false;
      }
    }
    return true;  
  }
}

console.log(test_prime(37));

Sample Output:

true

Flowchart:

Live Demo:

See the Pen JavaScript -Counts the number of vowels within a string-function-ex- 7 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04