how to use split with two different inputs

how to use split with two different inputs

i have any question,

like me there are two inputs
1. no_po = BMM / TRX001
2. no_po = BMM-RF-1
this is what I use
1. the code I take by using split or splitting data in two and I take it in the first array,
2. how can I get the second number from the second no_po or the second array

View

<div class= "form-group row">
<label class= "col-lg-4 col-form-label" for= "reference_code">Nomor PO<span class= "text-danger">*</span></label>
<div class= "col-lg-6">
<select name= "reference_code" class= "form-control" id= "reference_code">
<option value= "">----- Select PO -----</option>
@ foreach ( $get_po as $po)
<option value= "{{ $po-> no_po }}">{{ $po-> no_po }} / {{ customer_name( $po-> kode_customer) }}</option>
@ endforeach
</select>
</div>
</div>
<div class= "form-group row">
<label class= "col-lg-4 col-form-label" for= "select_company">Select Company <span class= "text-danger">*</span></label>
<div class= "col-lg-6">
<select class= "form-control" name= "select_company" id= "" required>
<option value= "">-- Silahkan pilih Nomor PO terlebih dulu --</option>
</select>
</div>
</div>

Jquery
$(document). ready( function() {
$( 'select[name="reference_code"]'). on( 'change', function() {
var no_po = $(this). val();
var result = no_po. split( '/');

var iki = result[ 1];
if(iki) {
$. ajax({
url: '{{ url("contract/get_no_po") }}/'+iki,
type: "GET",
dataType: "json",
success: function(data) {
$( 'select[name="select_company"]'). empty();
$. each(data, function(key,value) {
$( 'select[name="select_company"]'). append( '<option value="'+ key + '">'+ value + '</option>');
});
}
});
} else{
$( 'select[name="select_company"]'). empty();
}
});
});

please, help me!