我的代码通常在本地WAMP SERVER服务器上，但它不运行任何Web服务器

Question

function addRow() {
    $("#addRowBtn").button("loading");

    var tableLength = $("#productTable tbody tr").length;

    var tableRow;
    var arrayNumber;
    var count;

    if(tableLength > 0) {
        tableRow = $("#productTable tbody tr:last").attr('id');
        arrayNumber = $("#productTable tbody tr:last").attr('class');
        count = tableRow.substring(3);
        count = Number(count) + 1;
        arrayNumber = Number(arrayNumber) + 1;                  
    } else {
        // no table row
        count = 1;
        arrayNumber = 0;
    }

    $.ajax({
        url: 'php_action/fetchProductData.php',
        type: 'post',
        dataType: 'json',
        success:function(response) {
            $("#addRowBtn").button("reset");            

            var tr = '<tr id="row'+count+'" class="'+arrayNumber+'">'+                          
                '<td>'+
                    '<div class="form-group">'+

                    '<select class="form-control" name="productName[]" id="productName'+count+'" onchange="getProductData('+count+')" >'+
                        '<option value="">~~SELECT~~</option>';
                        // console.log(response);
                        $.each(response, function(index, value) {
                            tr += '<option value="'+value[0]+'">'+value[1]+'</option>';                         
                        });

                    tr += '</select>'+
                    '</div>'+
                '</td>'+
                '<td style="padding-left:20px;"">'+
                    '<input type="text" name="rate[]" id="rate'+count+'" autocomplete="off" disabled="true" class="form-control" />'+
                    '<input type="hidden" name="rateValue[]" id="rateValue'+count+'" autocomplete="off" class="form-control" />'+
                '</td style="padding-left:20px;">'+
                '<td style="padding-left:20px;">'+
                    '<div class="form-group">'+
                    '<input type="number" name="quantity[]" id="quantity'+count+'" onkeyup="getTotal('+count+')" autocomplete="off" class="form-control" min="1" />'+
                    '</div>'+
                '</td>'+
                '<td style="padding-left:20px;">'+
                    '<input type="text" name="total[]" id="total'+count+'" autocomplete="off" class="form-control" disabled="true" />'+
                    '<input type="hidden" name="totalValue[]" id="totalValue'+count+'" autocomplete="off" class="form-control" />'+
                '</td>'+
                '<td>'+
                    '<button class="btn btn-default removeProductRowBtn" type="button" onclick="removeProductRow('+count+')"><i class="glyphicon glyphicon-trash"></i></button>'+
                '</td>'+
            '</tr>';
            if(tableLength > 0) {                           
                $("#productTable tbody tr:last").after(tr);
            } else {
                $("#productTable tbody").append(tr);
            }       

        } // /success
    }); // get the product data

} // /add row

How to proceed in this case? Is there an error?

I get error:

Failed to load resource: the server responded with a status of 500