HTTP Headers

HyperText Transfer Protocol (HTTP) is the method by which Web servers and Web browsers communicate with each other. Web pages are composed of a header and a body. The header contains information about the body so that the Web browser will know how to treat the body of the page.

Using HTTP Headers

When a Web browser requests a simple HTML page, the Web server generates the HTTP header information, and the body is the content of the HTML page requested. When the Web browser requests a CGI script, the CGI programmer must supply the header and body information.

An HTTP header is separated from the body of the page by a blank line. In Perl, two newline characters, \n\n, indicate this line.

The following are some of the HTTP headers most commonly used by CGI programmers:

Content-type: type/subtype

The Content-type header indicates the kind of content included in the body of the page. The type/subtype declaration is also known as a MIME type.

If the body of the Web page is going to be HTML content, use the following header:

Content-type: text/HTML

Location: uri

The Location header indicates the absolute URI of a Web page. A URI stands for Universal Resource Indicator; in most cases this is a URL.

More information

HTTP/1.1 includes the complete specification for HTTP. This is a very technical document, and is more detailed than most CGI programmers usually need.

Local information about MIME types is available within the UT Web Central FAQS.