Array and if-else statement issue

I have two forms, if $_POST['submit'] of the first form is click the second form is loaded and an array is assigned with $POST data of first form , else if the $_POST['submit'] of the second form is pressed the same array needs to have additional elements this time from $POST of second form, but the problem is that my array is getting empty as soon as the elseif is executed. I tried passing the array by reference but that did not help me.

 if(isset(btn_Of_Form1)) {
     echo "form2"; $my_arr =$_POST;
 }
 elseif(btn_of_Form2){
     $my_arr =array_merge($my_arr,$_POST);
 开发者_运维知识库}

You can use $_SESSION and serialize:

session_start();

if(isset(btn_Of_Form1))
{
    echo "form2";
    $_SESSION['data'] = serialize($_POST);
}
elseif(btn_of_Form2)
{
    $my_arr = unserialize($_SESSION['data']);
    $my_arr = array_merge($my_arr,$_POST);
}