Passing Data to a CGI Script

As mentioned above there are a few ways to pass data to a CGI script.

Path Information and Arguments of a CGI Script call are explicit -- you (or the HTML Form) have to actually specify the information ad part of the call.

Standard input and Environment variables are more transparent -- we will need to deal with accepting the input within the CGI script.

Let's consider the arguments of a CGI script call further for the moment.

The GET method of Form posting or a direct URL call to a CGI script may use this method.

NOTE: Using the direct method of CGI Script call is a good way to debug possible Form/CGI script interaction problems.

There are several conventions adopted when passing arguments to a CGI script:

• Different fields (e.g. name value pairs are separated by a ampersand (&).
• Name/value pair assignments are denoted by an equals sign (=). The format is name=value.
• Blank spaces must be denoted by a plus sign +.
• Some special characters will be replaced by a percent sign (2 digit hexadecimal (ASCII Value) code. For example if you need to input an actual &,

The GET Form posting method does these things automatically.

You need to do these things yourself if call the CGI script direct from a URL.