cannot pass $_GET["pos"] in autocomplete combo

I’m trying autocomplete combo .

I was able to pass the value entered in the combo box.

However it does not return anything for $_GET[“pos”]
it always end up in 0
if (!isset($_GET[“pos”])) { $_GET[“pos”] = 0;}

Can someone help me fix this

“pos” will be greated than 0 if you’ve enabled autosuggestions (the 4th parameter of the enableFilteringMode method) and the last option in list is selected.