# Prime Number Check | Easily in JavaScript

## Prime Number Check

### What Prime Number?

Prime Number is a number that is divisible by only 1 and that number. Suppose 13 is a prime number, because 13 is divisible by 1 (13 % 1 == 0) and 13 is also divisible by 13 (13 % 13 == 0)

### 1. Check a number either it is prime or not

Here is code for isPrime function that will check either a number is prime or not.

### JavaScript Code for isPrime function

[code lang=”js”]
function isPrime(num) {
for(var i = 2; i < num; i++)
if(num % i === 0) return false;
return num !== 1 && num !== 0;
}
[/code]

### JavaScript Code for display prime number list from starting number to ending number using a for loop

[code lang=”js”]
function printPrimes(sn, en){
for(sn; sn <= en; sn++){
if(isPrime(sn)){
document.write(sn+"<hr/>");
}
}
}
printPrimes(1,100);

[/code]

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