lowest common divisor - in progress

gistfile1.txt

//Find the smallest number that is evenly divisble by  all numbers in the provided range.



 function smallestCommons(arr) {
    var primeArr =[];
    var compArr= [];
    for(var i = arr[0]; i <= arr[1]; i++){
        // call is prime function on each number and push prime one way and comp another
         if(isPrime(i)){
             primeArr.push(i);
            
         } else {
         compArr.push(i);
         
     }
   
 }
     return compArr;
 }
function isPrime(n) {
    if((n <= 3) &&( n > 0) ){return true;}
    var m = Math.sqrt(n);
    for(var i=2; i<= m; i++){
        if (n % i === 0){return false;}
    }    
         return true;
}

smallestCommons([1,5]);
// 1   =   1   =   11
// 2   =   2   =   21
// 3   =   3   =   31
// 4   =   2 * 2   =   22
// 5   =   5   =   51
// lcm(1, 2, 3, 4, 5)   =   1 * 2 * 2 * 3 * 5   =   11 * 22 * 31 * 51   =   60