7 replies to this topic

[Devilfish]

About headers. I've seen the term pop up here and there and I've looked it up with mah Google, but I can't find an explaination that I can really understand. Any of you internet-savvy people here want to explain to me, in layman's terms, what they are and why we have them? I'd be really grateful!

[iargue]

Header can relate to many things, but I will explain HTML Headers.

This relates to the first section on the HTML code, it usually contains Javascript that needs to run on the page, a title, and meta tags to identify the page.

Many robots (Computers designed to visit and index pages of the internet) will load just the header of a page, which gives them keywords, and a title.

This is an example of an html header.

<HTML>
   <HEAD>
      <TITLE>My first HTML document</TITLE>
   </HEAD>
   <BODY>
      <P>Hello world!
   </BODY>
</HTML>

In general, a header relates to data that is sent first, or that loads first. For instance, at the top of our page, you see a neocodex logo and a bunch of tabs you can click. This is our header, and it is sent first, on every page you load.

[kittycat]

you mean like [h1] ? [/h]
they are just used to separate, signify importance, a title, whatever... nothing important.

[iargue]

you mean like [h1] ? [/h]
they are just used to separate, signify importance, a title, whatever... nothing important.

I hope you never become a teacher.

[Noitidart]

Do you mean http headers? like headers that are sent whenever your internet makes a connectin?

[Melchoire]

If you're referring to HTTP headers they're blocks of data sent back and fort between client and server in order to communicate what data to exchange. I can elaborate further if you want...

[Andy]

Umm, long explanation coming up, sorry if I bore you.

When a web browser connects to a web server (ie computers with files on them which browsers can take files from), it needs to give the server information about the file it wants to retrieve, for example a browser which wants to get index.html from example.com, it will send these request headers to the example.com server.

GET /index.html HTTP/1.1
Host: www.example.com

this is the simplest possible request header.

The lines are separated by a CRLF (0x0D 0x0A) and the request is stopped with a double newline.

The server will then return something such as this:

HTTP/1.1 200 OK
Date: Mon, 23 May 2005 22:38:34 GMT
Server: Apache/1.3.3.7 (Unix)  (Red-Hat/Linux)
Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT
Etag: "3f80f-1b6-3e1cb03b"
Accept-Ranges: bytes
Content-Length: 438
Connection: close
Content-Type: text/html; charset=UTF-8

<content>

Each line as above is separated by a crlf as mentioned above.

A server response is followed by a blank line and text of the requested page. The ETag (entity tag) header is used to determine if a cached version of the requested resource is identical to the current version of the resource on the server. Content-Type specifies the Internet media type of the data conveyed by the http message, while Content-Length indicates its length in bytes. The HTTP/1.1webserver publishes its ability to respond to requests for certain byte ranges of the document by setting the header Accept-Ranges: bytes. This is useful if the client needs to have only certain portions[8]of a resource sent by the server, which is called byte serving. When Connection: close is sent in a header, it means that the web server will close the TCP connection immediately after the transfer of this package.

From Wikipedia

For more information:

• Google Search HTTP
• Google Search HTTP Headers

[Devilfish]

I did mean HTTP headers, I should have specified. Thanks for the answers everyone!