What are the best practices for accessing variables passed through URLs in PHP scripts?

When accessing variables passed through URLs in PHP scripts, it is important to sanitize and validate the input to prevent security vulnerabilities such as SQL injection or cross-site scripting attacks. One common method is to use the $_GET superglobal array to access URL parameters and then apply filtering functions like htmlentities() or htmlspecialchars() to sanitize the input. 

// Example of accessing and sanitizing a variable passed through a URL
if(isset($_GET['user_id'])) {
    $user_id = htmlentities($_GET['user_id']);
    // Use $user_id in your script
}

Keywords

super global $_GET $_POST URL parameters data validation

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