Question

我有一个用于更改用户数据的PHP表单，没有必填字段。我想检查用户是否在表单的字段中输入数据。

我最初的想法是，如果用户点击提交已经离开了一些如果字段为空，则POST方法将输入NULL值 $ _POST ['field']变量。

因此我检查了$ POST ['field']变量是否使用'isset'功能设置。不幸的是，看起来，POST方法不会在表单中未指定的变量中输入NULL值。这使得if（isset（$ [POST））语句为真，因为POST方法确实为这些变量设置了一些值。

有关如何检查用户是否在字段中输入数据的任何想法？这是我的代码：

<?php 
include 'core/init.php';
//logged_in_redirect();
include 'includes/overall/admin_start.php';
?>

<h2>Employee information: </h2>
<?php 
echo "Username: ", $_SESSION['user_data']['username'], "<br>";
echo "First name: ", $_SESSION['user_data']['first_name'], "<br>";
echo "Last name: ", $_SESSION['user_data']['last_name'], "<br>";
echo "Email: ", $_SESSION['user_data']['email'], "<br>";
echo "City: ", $_SESSION['user_data']['city'], "<br>";
echo "Type: ", $_SESSION['user_data']['type'], "<br>";

?>

<h2> Alter information: </h2>

<?php

if(empty($_POST) === true){
    echo "print";
}
else{
    if(isset($_POST['username'])){
        if(user_exists($_POST['username']) === true){
            $errors[] = 'Sorry, the username \'' . $_POST['username'] . '\' 
is already taken.';
        }
        if(preg_match("/\\s/", $_POST['username']) == true){
            $errors[] = 'Your username must not contain any spaces.';
        }
        if(strlen($_POST['username']) > 30){
            $errors[] = 'The size of one of your entries is not acceptable. 
Entry size must be smaller than 30 characters.';
        }
    }
    if(isset($_POST['password'])){
        //echo $_POST['password'];
        if(strlen($_POST['password']) < 6){
            $errors[] = 'Your password size is not acceptable. Password size 
must be between 6 and 30 characters.';
        }
        if($_POST['password'] !== $_POST['repeat_pass']){
            $errors[] = 'Your password entries do not match.';
        }
        if(strlen($_POST['password']) > 30){
            $errors[] = 'The size of one of your entries is not acceptable. 
Entry size must be smaller than 30 characters.';
        }
    }
    if(isset($_POST['email'])){
        if(filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) === false){
            $errors[] = 'A valid email address is required.';
        }
        if(email_exists($_POST['email']) === true){
            $errors[] = 'Sorry, the email \'' . $_POST['email'] . '\' is 
already in use.';
        }
        if(strlen($_POST['email']) > 30){
            $errors[] = 'The size of one of your entries is not acceptable. 
Entry size must be smaller than 30 characters.';
        }
    }
    if(isset($_POST['type'])){
        if(($_POST['type'] !== "1") && ($_POST['type'] !== "2") && 
($_POST['type'] !== "3")){
            $errors[] = 'Please insert a correct number in the field type';
        }
    }
    if(isset($_POST['city'])){
        if(city_exists($_POST['city']) === false){
            $errors[] = 'Sorry, there is no shop in the specified city';
        }
        if(strlen($_POST['city']) > 30){
            $errors[] = 'The size of one of your entries is not acceptable. 
Entry size must be smaller than 30 characters.';
        }
    }
}
?>

<?php
if(isset($_GET['success']) && empty($_GET['success'])){
    echo 'You have altered the employee successfully';
}
else
{
    if(empty($_POST) === false && empty($errors) === true)
    {
        if(isset($_POST['username'])){$register_data['username'] = 
$_POST['username'];}
        if(isset($_POST['password'])){$register_data['password'] = 
$_POST['password'];}
        if(isset($_POST['first_name'])){$register_data['first_name'] = 
$_POST['first_name'];}
        if(isset($_POST['last_name'])){$register_data['last_name'] = 
$_POST['last_name'];}
        if(isset($_POST['email'])){$register_data['email'] = 
$_POST['email'];}
        if(isset($_POST['city'])){$register_data['city'] = $_POST['city'];}
        if(isset($_POST['type'])){$register_data['type'] = $_POST['type'];}


        alter_user($register_data);
        header('Location: alter_employee.php?success');
    }
    else{echo output_errors($errors);}
?>

<form action="" method="post">
    <ul>

        <li>
            Username:<br>
            <input type="text" name="username">
        </li>
        <p><li>
            Password:<br>
            <input type="password" name="password">
        </li></p>
        <p><li>
            Repeat password*:<br>
            <input type="password" name="repeat_pass">
        </li></p>
        <p><li>
            First name:<br>
            <input type="text" name="first_name">
        </li></p>
        <p><li>
            Last name:<br>
            <input type="text" name="last_name">
        </li></p>
        <p><li>
            Email:<br>
            <input type="text" name="email">
        </li></p>
        <p><li>
            City:<br>
            <input type="text" name="city">
        </li></p>
        <p><li>
            Type (1,2,3):<br>
            <input type="text" name="type">
        </li></p>
        <p><li>
            <input type="submit" value="Register">
        </li></p>

    </ul>

</form>

<?php 
}
include 'includes/overall/end.php'; ?>

Answer 1

例如，你可以这样做：

$foo = (!isset($_POST['foo']) || empty($_POST['foo'])) ? 'default value' : $_POST['foo'];

您检查它是否未设置并提供默认值，否则使用已发布的值填充变量。

Answer 2

避免使用empty，因为它还会检查0和"0"等虚假条件，只使用isset不会捕获空字符串。最好检查空输入的预期值，例如

if (isset($_POST['fieldName']) && trim($_POST['fieldName']) !== "") {
    echo "There's something here!";
}

Answer 3

以上都不对我有用。但是，我这样做： if（$ _ POST ['foo']！=“空”）这就是窍门。我发现这个是因为我试图 echo“值是”。$ _ POST ['foo']。“。
” 并不断得到 “值为空” 当我没有传递真实的字符串时。

当表单留空时，PHP Post值

3 个答案: