Multiples of 3 and 5

Multiples of 3 and 5

// 12/22/2015
// Multiples of 3 and 5

// If we list all the natural numbers below 10 that are multiples 
// of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

// Find the sum of all the multiples of 3 or 5 below 1000.

// My Solution:

function multisum(num){
    var arr1=[];
    var total=0;
    
    for(var i=0; i<num; i++){
        
        if(i%5==0||i%3==0){
            arr1.push(i)
        }
    }
    
    for(var j=0; j<arr1.length;j++){
        total+=arr1[j]
    }
    return total;
    
}

multisum(15)
//3,5,6,9,10,12