$arr1 = [1 , 3, 5, 9, 10, 12 ];
$arr2 = [2 , 4, 5, 7, 2];


// /* Arrays: finding unique elements from the first array */

function FindCommonElements($arr1, $arr2) {

$arr1size = count($arr1)-1;
$arr2size = count($arr2)-1;
$temp;

    for ($i=0; $i<=$arr1size; $i++){
        $temp = $arr1[$i];
        for ($j=0; $j <= $arr2size;  $j++){
            //code
        }
    }
}

 echo FindCommonElements($arr1, $arr2);