Why is it important to differentiate between input validation and output escaping when handling user inputs in PHP?

It is important to differentiate between input validation and output escaping in PHP because they serve different purposes. Input validation helps ensure that the data being submitted by users is in the correct format and meets certain criteria, while output escaping helps prevent malicious code from being executed when the data is displayed on a webpage. By properly implementing both input validation and output escaping, you can protect your application from security vulnerabilities such as SQL injection and cross-site scripting attacks. 

// Input validation example
$username = $_POST['username'];
if (empty($username)) {
    // handle error
}

// Output escaping example
echo htmlspecialchars($username, ENT_QUOTES, 'UTF-8');

Keywords

input validation output escaping user inputs PHP security

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