<?php session_start(); require_once 'db.php'; if($_SESSION['user_id']==null) { header("Location:index.php"); } $btc_address=$_POST["btc_address"]; $user_name=$_POST["username"]; //echo "user " . $user_name . " address " . $btc_address; $sql="UPDATE user SET btc_address ='$btc_address' WHERE username='$user_name';"; $result=mysqli_query($conn,$sql); ?> <script> alert("Thank you,address set"); window.location.replace("charts.php"); </script> <?php mysqli_close($conn); ?>