So let's say I have my first array (arrayOne) with the values of [1,2,3,3,4,2]. I need to compare this array to another array to check for duplicate values (arrayTwo), then display these values.

So, the final output would be: 1, 2, 3, 4.

The catch is I can only use really basic methods, pretty much just booleans, multiple functions, and loops. 

How might I go about this? Searching the internet brings up code similar to this:

```
for (a = 0; a < array1.length; a += 1) {
    for (b = 0; b < array2.length; b += 1) {
        if (array1[a] !== array2[b])
            array2 = array1
        }
    }
}

output = array2   

```

... so on so forth, but this doesn't seem to work for me (note my code is not exactly like this, but after searching, this seems to be close to what I am looking for).

Any advice?