processFiles.php

<?php
session_start();
	if ( isset( $_POST['uploadProjectSelect'] ) ) {
	$uploadProjectSelect = $_POST['uploadProjectSelect'];
	
	$valid_formats = array("mp3");
	$max_file_size = 2*1024*1000; //100 kb
	$path = "uploaded_files/"; // Upload directory

	if (!file_exists($path . $uploadProjectSelect)) {
		mkdir($path . $uploadProjectSelect, 0777, true);
		$path = $path . $uploadProjectSelect . "/";
	}else{
		$path = $path . $uploadProjectSelect . "/";
	}
	$count = 0;

	

	if(isset($_POST) and $_SERVER['REQUEST_METHOD'] == "POST"){
		// Loop $_FILES to exeicute all files
		foreach ($_FILES['files']['name'] as $f => $name) {     
			if ($_FILES['files']['error'][$f] == 4) {
				continue; // Skip file if any error found
			}	       
			if ($_FILES['files']['error'][$f] == 0) {	           
				if ($_FILES['files']['size'][$f] > $max_file_size) {
					$message[] = "$name is too large!.";
					continue; // Skip large files
				}
				elseif( ! in_array(pathinfo($name, PATHINFO_EXTENSION), $valid_formats) ){
					$message[] = "$name is not a valid format";
					continue; // Skip invalid file formats
				}
				else{ // No error found! Move uploaded files 
					if(move_uploaded_file($_FILES["files"]["tmp_name"][$f], $path.$name))
					$count++; // Number of successfully uploaded file
					header('Location: index.php#upload/'.$uploadProjectSelect);
					echo "<h1>Upload successful</h1>";
					}
				}
			}
		}

}
?>