What is a HTTP Server Header
HTTP server headers are a hidden part of a webpage response that only a browser can see, and show nowhere when a user normally opens any website or web page. HTTP headers are a piece of code that tells the browser what the browser's behavior should be when opening the requested page. There are several HTTP headers that are used to modify the browser, and some of them are Access-Control-Allow-Origin, Access-Control-Max-Age, Age, Cache-Control, Content-Language, Content-Length, Content-Type, Expires, Location, Server, Set-Cookie, Transfer-Encoding, X-Frame-Options and many more. A browser may or may not send all headers at once, and it is up to the server and webmaster configuration how and when they want to send a specific header depending on the scenarios. For example, sometimes a webmaster wants to specify the cache time for a specific page, and passes the Expiration Header which tells the browser to cache the resource and not always request the resource from the web server on every request from the same user. In this way, the other HTTP headers also provide many modifications that a webmaster can make to the user's browser with respect to the web page.