php - 尝试将变量打印到 HTML 中时 undefined variable

Question

PHP

if($count == 1) {
     session_register("username");
     $_SESSION['username'] = $username;

     header("location: ../home");
  }else {
     $error = "Your Login Name or Password is invalid";
  }

HTML -- 第 43 行

<?php echo "<p class='text-danger'>$error</p>"; ?>

Notice: Undefined variable: error in directory on line 43

Answer 1

Error occurred because, when if statement is true then only under if statement block code would be executed not else block code. So $error variable did not initialized. Each variable should be initialized if you want to use it. $error variable did not initialize but you use it in HTML-- line 43. Thanks

  $error ="";
  if($count == 1) {
     session_register("username");
     $_SESSION['username'] = $username;

     header("location: ../home");
  }else {
     $error = "Your Login Name or Password is invalid";
  }