我需要帮助以php + ajax填充3个依赖的动态文件夹下拉列表

Question

It would be great hep for me if any one can help me, I have a directory with 3 main folders A,B,C and Sub folders A1,A2,A3 in A folder like wise.., When the user select the folder A from 1st drop down,the Second drop down should be populated with sub folders in the Folder A.After Selecting second drop down the third drop down should be populated with sub sub folders on selection of sub sub folder and submit the files has to be displayed on the page with link to open the file. I know this would be done with the help of Ajax call,But i was a starter to php Kindly help me please... Also a alternate approach I have tried using glob function

I dont know whats wrong with the Code no files are displaying in the page..

<?php

Session_start();
Error_reporting(E_ALL & ~E_NOTICE);
$reportname  = $_POST['Rep'];
$year  = $_POST['year'];
$customer  = $_POST['cus'];
$month= $_POST['month'];
$path= ".."."/".$reportname."/".$year."/".$customer."/".$month."/"; 
echo $path ."<br/>";
$files = glob($path."*.xlsx");
foreach($files as $file)
 {
echo $file;
 }
?>

Answer 1

$("#dropdown1").on("change", function() {

  $.ajax({
    url: "phpfile.php",
    type: 'POST',
    data: {
      folder: $(this).val()
    }
    success: function(data) {
      $("#dropdown2").html(data);
    }
  });
});

In phpfile.php

$fileslist = scandir($_POST['folder']);
$str = "";
foreach($fileslist as $file) {
  if (is_dir($file)) {
    $str. = "<option>$file<option>";
  }
}
echo $str;