[Shedi]

1. Use Content Security Policy (CSP) to Prevent XSS
Add a CSP header to restrict sources of scripts and content that can run on your website.

Code:

<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:;">

This prevents unauthorized scripts from running on your site.

2. Enable HTTP Strict Transport Security (HSTS)
Ensure your website always uses HTTPS for secure communication.

Code:

<meta http-equiv="Strict-Transport-Security" content="max-age=31536000; includeSubDomains">

3. Disable Browser Caching for Sensitive Data
Prevent sensitive data from being stored in browser cache.

Code:

<meta http-equiv="cache-control" content="no-cache, no-store, must-revalidate">
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="expires" content="0">

4. Secure iFrames with X-Frame-Options
Prevent clickjacking by disallowing your site to be embedded in iframes.

Code:

<meta http-equiv="X-Frame-Options" content="SAMEORIGIN">

5. Prevent Cross-Site Scripting (XSS)
Escape all user input. Use the sanitize and escape functions in your code. In HTML forms, you can enforce proper input validation:

Code:

<input type="text" name="username" required pattern="[a-zA-Z0-9]{5,20}" title="Only alphanumeric characters, 5-20 characters long.">

6. Prevent MIME-Type Sniffing
Ensure that browsers only interpret files as their declared content type.

Code:

<meta http-equiv="X-Content-Type-Options" content="nosniff">

7. Use Secure Cookies
Set secure flags on cookies to prevent interception during transmission.

Code:

setcookie("user", "value", ["secure" => true, "httponly" => true, "samesite" => "Strict"]);

8. Implement Form CSRF Protection
Use a hidden token field to validate form submissions:

Code:

<input type="hidden" name="csrf_token" value="your_token_here">

9. Restrict Directory Access
Ensure no sensitive files or directories are exposed using .htaccess rules:
Options -Indexes
10. Secure Login Page with Autocomplete Off
Prevent browsers from storing sensitive data on your login form.

Code:

<form autocomplete="off">
  <input type="password" name="password" autocomplete="new-password">
</form>

Conclusion
Applying these HTML and meta tags improves your website security and protects against common threats like XSS, clickjacking, and data theft. Combine them with server-side security measures for comprehensive protection.