JSFiddle - React, Tailwind, and code Playground

JavaScript

session_start();
if(!isset($_SESSION['myusername'])){
header("location:/mainlogin.php");
}
require_once "Mail.php";
$hostname="";
$username="";
$password="";
$database="";

if (!empty($_POST['name'])){
$member = $_POST['name'];
$memval = 1;
}
function returnBack(){
	
	header("Location:/csvuploaderform.php?seterror=1");
	exit;

}
function returnBackfile(){
	
	header("Location:/csvuploaderform.php?seterror=2");
	exit;

}

if (isset($_POST['submit'])){
	
	/*******************************CHECK TO MAKE SURE FORM IS PROPERLY FILLED AND GET NAME OF COLUMNS IN CSV FILE *********************************************************/
	
	if (!empty($_FILES['file']['error'] ) )
	{
		
		echo "file";
		$seterror =1;
   		returnBack();
	
	} 
	if (empty($_POST['firstname'])){
		
		$seterror =1;
		returnBack();
	}
	if (empty($_POST['lastname'])){
		$seterrro =1;
		
		returnBack();
	}
	if (empty($_POST['email'])){
		$seterror =1;

		returnBack();
	}
	if (empty($_POST['phone'])){
		$seterror =1;
		returnBack();
	}
	if ($seterror != 1){
		
	$file = $_FILES['file']['tmp_name'];	
	
	$handle = fopen($file , "r");
	
	$fileop = fgetcsv($handle,1000,",");
	
	$fileop=array_map("strtoupper",array_map("trim",$fileop));
	
	$firstname_index = array_search(strtoupper($_POST["firstname"]),$fileop);
	if ($firstname_index===false){
		returnBack();
	}
	$lastname_index = array_search(strtoupper($_POST['lastname']),$fileop);
	if ($lastname_index===false){
		
		returnBack();
	}
	$email_index = array_search(strtoupper($_POST['email']),$fileop);
	if ($email_index===false){
		
		returnBack();
	}
	$phone_index = array_search(strtoupper($_POST['phone']),$fileop);
	if ($phone_index===false){
		
		returnBack();
	}
	$date = date("Y-m-d");  
	/***********************ASSIGN COLUMN VALUES TO ACCORDING VARIABLES AND INSERT THEM INTO CSV TABLE IN DB *************************************/
	try {  
  # MySQL with PDO_MYSQL  
  $DBH = new PDO("mysql:host=$hostname;dbname=$database", $username, $password);  
 ...