未定義的變量：用戶

Question

似乎無法找到問題的答案。我已經將$ user聲明爲全局變量，然後通過cookie（如果存在）或通過表單設置它，然後我稱之爲啓動函數。 在開始函數中我回顯了它的一部分，但我得到了未定義變量：即使我已經定義了它。

<?php 
    global $user; 
    function ConsoleLog($message) 
    { 
     echo '<script>console.log("' . $message. '")</script>'; 
    } 
    if (isset($_COOKIE["user"])){ 
     $user = unserialize($_COOKIE["user"]); 
     start(); 
     } 
    else{ 
      if (isset($_POST['submit'])) 
    { 
     $user = array(
     "name" => $_POST['name'], 
     "class" => $_POST['class'], 
     "school" => $_POST['school'], 
     ); 
     $expire=time()+60*60*24*365; 
     setcookie("user",serialize($user), $expire); 
     start(); 
    } 
    else 
    { 
      echo "Welcome new user!\n<br/>"; 
      echo '<form method="post"> 
    Name: <input type="text" name="name"> 
    Class:<select name="class"> 
     <option value="9">9</option> 
    </select> 
    School: <input type="text" name="school"> 
    <input type="submit" name="submit"> 
    </form>'; 
    } 
    } 
    function start(){ 
     echo "Your name: " . $user['name'] . "!\n<br/>"; 
     echo "Your class: " . $user['class'] . "\n<br/>"; 
     echo "Your school: " . $user['school'] . "\n<br/>"; 
     ?> 
     <hr/> 
     <h2>HomePage</h2> 
     <?php 
    } 
    ?> 

Answer 1

用法 -

$user = 'something'; 

function someFunction(){ 
    global $user;  // here global will make $user var accessible inside function. 
    echo $user; 
} 

如果你只是想使變量全球，外界把它定義 -

define("USER","SOMETHING"); 

這將僅僅通過訪問 -

echo USER; 

Answer 2

當你調用函數的start（）也傳遞參數：

if (isset($_COOKIE["user"])){ 
    $user = unserialize($_COOKIE["user"]); 
    start($user); 
    } 

或任何要調用該函數使用：start($user);

而變化接受參數的函數：

function start($array){ 
     echo "Your name: " . $array['name'] . "!\n<br/>"; 
     echo "Your class: " . $array['class'] . "\n<br/>"; 
     echo "Your school: " . $array['school'] . "\n<br/>"; 
     ?> 
     <hr/> 
     <h2>HomePage</h2> 
     <?php 
    } 

Answer 3

您不能將變量聲明爲全局變量，它不會以這種方式工作。

相反，您需要將global $user作爲參數或將其作爲參數傳遞給每個函數，或者將其存儲在超全局像$_SESSION中。作爲最後的手段，您可以使用$GLOBALS['user']，但這很貴。

Answer 4

if !isset($_COOKIE["user"]) and !isset($_POST['submit']) then $user will undefined。因此，在start()時，您指的是未定義的$user陣列中的按鍵。

另外，在全局空間中調用global $user沒有意義，應該將其移入使用該變量的每個函數，例如，

function start() { 
    global $user; 
    // ... 
} 

Answer 5

要做到這一點，你想在每個你想使用全局變量的函數中聲明它在函數的開頭。全球

function start(){ 
    global $user; 
    ... 
} 

Answer 6

這是您的代碼

<?php 
    global $user; 
    function ConsoleLog($message) 
    { 
     echo '<script>console.log("' . $message. '")</script>'; 
    } 
    if (isset($_COOKIE["user"])){ 
     $user = unserialize($_COOKIE["user"]); 
     echo "Your name: " . $user['name'] . "!\n<br/>"; 
     echo "Your class: " . $user['class'] . "\n<br/>"; 
     echo "Your school: " . $user['school'] . "\n<br/>"; 
      } 
    else{ 
      if (isset($_POST['submit'])) 
    { 
     $user = array(
     "name" => $_POST['name'], 
     "class" => $_POST['class'], 
     "school" => $_POST['school'], 
     ); 
     $expire=time()+60*60*24*365; 
     setcookie("user",serialize($user), $expire); 
     echo "Your name: " . $user['name'] . "!\n<br/>"; 
     echo "Your class: " . $user['class'] . "\n<br/>"; 
     echo "Your school: " . $user['school'] . "\n<br/>"; 
     } 
    else 
    { 
      echo "Welcome new user!\n<br/>"; 
      echo '<form method="post"> 
    Name: <input type="text" name="name"> 
    Class:<select name="class"> 
     <option value="9">9</option> 
    </select> 
    School: <input type="text" name="school"> 
    <input type="submit" name="submit"> 
    </form>'; 
    } 
    } 

     ?> 
     <hr/> 
     <h2>HomePage</h2> 

Answer 7

我想你在這個不同的答案困惑，最簡單的答案是如下：

<form method="" enctype="multipart/form-data"> 

寫form標籤。