How does security headers work internally in JavaScript?

Security headers are used in web applications to control the interactions of browsers with your site. They provide various mechanisms to mitigate common vulnerabilities and enhance the security of web applications. In JavaScript, understanding and implementing these headers is crucial for preventing attacks such as Cross-Site Scripting (XSS) and Clickjacking.

Here's a brief overview of some important security headers:

• Content-Security-Policy (CSP): This header allows you to specify which content sources are considered valid. It helps in preventing XSS attacks by whitelisting sources from which scripts can be loaded.
• X-Content-Type-Options: Setting this header to 'nosniff' instructs the browser not to automatically detect MIME types and encourages it to strictly follow the specified content type.
• X-Frame-Options: This header controls whether your site can be embedded in an iframe, preventing Clickjacking attacks.
• Strict-Transport-Security (HSTS): This header enforces secure (HTTPS) connections to the server and encourages browsers to refuse any non-secure (HTTP) connections.