What common beginner mistakes should be avoided when handling URLs in PHP forms?

Common beginner mistakes when handling URLs in PHP forms include not properly sanitizing user input, not validating URLs, and not properly encoding URLs before outputting them. To avoid these issues, always sanitize and validate user input to prevent malicious code injection and ensure that URLs are properly formatted. Additionally, use functions like urlencode() or htmlspecialchars() to encode URLs before displaying them to users. 

// Sanitize and validate URL input
$url = filter_input(INPUT_POST, 'url', FILTER_SANITIZE_URL);
if (filter_var($url, FILTER_VALIDATE_URL)) {
    // URL is valid, proceed with further processing
} else {
    // Invalid URL, handle error accordingly
}

// Encode URL before outputting
echo htmlspecialchars($url);

Keywords

URL validation form handling PHP superglobals htmlspecialchars URL encoding

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