I have two arrays:

```
var array1= [1,3,5,7,9,11]
var array2= [undefined,4,6]

```

I need to merge one element of the array1, then one element of the array2, etc. This is my code:

```
function mergeArrays(array1, array2){
    var array3 = []; 
    maxlength = Math.max(array1.length, array2.length);

for(i=0;i<maxlength;i++){   
    array3.push(array1[i]);  
    array3.push(array2[i]);
}      
    return console.log(array3);
}

```

The output now is:

```
array3 = [1,undefined,3,4,6,7,undefined,9,undefined,11,undefined]

```

I need the output to be:

```
array3 = [1,undefined,3,4,6,7,8,11]

```

I mean, I can't use ( != undefined), because if I have an undefined in the middle of the array it has to be there.