Tips to avoid PHP verification code not being displayed after copying and pasting it

Tricks to avoid PHP verification codes not being displayed after copying and pasting them

With the development of the Internet, verification codes are widely used in various websites and applications. An effective way to protect against malicious bot attacks. In PHP development, common verification code functions include numbers, letters, combination verification codes, etc. However, sometimes when copying and pasting the verification code on the web page, the problem will not be displayed. This article will introduce some techniques to help developers avoid PHP verification codes that are not displayed after copying and pasting them, and provide specific code examples.

Problem Analysis

On the web page, users may encounter situations where they need to enter a verification code, such as registering an account, submitting a form, etc. When the user sees the verification code, they will copy and paste it into the input box to ensure the accuracy of the input. However, sometimes after pasting the verification code, it is not displayed on the web page, causing the user to be unable to confirm whether the correct verification code has been entered, which brings trouble to the user experience.

Solution

1. Use Session to store verification code

A common solution is to save the verification code in Session when generating the verification code, and then While the verification code image is displayed on the page, the value of the verification code is stored in the Session. When the user pastes the verification code in the input box, the verification code entered by the user is verified through the value in the Session.

// 生成验证码
session_start();
$randomCode = mt_rand(1000, 9999);
$_SESSION['captcha'] = $randomCode;

// 在页面上显示验证码图片
header('Content-type: image/png');
$image = imagecreate(100, 30);
$bgColor = imagecolorallocate($image, 255, 255, 255);
$textColor = imagecolorallocate($image, 0, 0, 0);
imagestring($image, 5, 10, 5, $randomCode, $textColor);
imagepng($image);
imagedestroy($image);

2. Verification code verification

When the user submits the form, verify whether the verification code entered by the user is consistent with the verification code stored in the Session.

session_start();
if ($_POST['captcha'] == $_SESSION['captcha']) {
    // 验证码正确，继续后续操作
} else {
    // 验证码错误，给出提示并刷新验证码
}

3. Add a refresh verification code button

In order to facilitate users to re-obtain the verification code when the verification code is not displayed or is wrong, you can add a refresh verification code button. Click the button to regenerate it. and display the new verification code.

<button onclick="location.reload();">刷新验证码</button>

Through the above method, you can effectively avoid the situation where the PHP verification code does not display after copying and pasting it, while improving user experience and website security. I hope this article can be helpful to PHP developers in implementing the verification code function.

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