What are some best practices for handling HTML content in PHP to prevent security vulnerabilities or unexpected behavior?

When handling HTML content in PHP, it is important to sanitize and validate user input to prevent security vulnerabilities such as cross-site scripting (XSS) attacks. One way to do this is by using functions like htmlspecialchars() to encode special characters in the HTML content. Additionally, using a Content Security Policy (CSP) header can help mitigate the risks of XSS attacks by specifying which sources are allowed to load content on a web page. 

// Sanitize HTML content using htmlspecialchars()
$htmlContent = "<script>alert('XSS attack!');</script>";
$sanitizedContent = htmlspecialchars($htmlContent, ENT_QUOTES, 'UTF-8');

echo $sanitizedContent;

Keywords

XSS htmlentities htmlspecialchars strip_tags content security policy

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