JavaScript. How to Compare Input Arrays

Question

I\'m stuck with this problem for 3 days now... Someone please help me.

Challenge 5
Construct a function intersection

Answer 1

I think you want the common elements. Let me show you how:

var Array1 = [5, 10, 15, 20]
var Array2 = [15, 88, 1, 5, 7]
var Array3 = [1, 10, 15, 5, 20]
var found = []
var Final = []
var c = 1;e = 1;
for (i = 1;i<=Array1.length;i++){
    for (k = 1;k<=Array2.length;i++){
        if (Array1[i] == Array2[k]){
            Found[c] = Array[i];
            c++;
        }
    }
}
for (n = 1;n <= Found.length ; n++){
    for (m = 1;m <= Array3.length ; n++){
        if (Found[n] == Array3[m]){
            Final[e] = Found[n]
            e++; 
        }
    }
}
//the Array Final Contains 5 , 15