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is a connection (stream) with the executable file, the text goes to the client instead of the server monitor. However, before you send the required text, you must first send the following information:

Content-Type: text/html\n\n

This explains why you have the first print statement. The required text is in the variable, $value. The second print statement sends the required text.

Illustration with PHP
There are two PHP programs below. Each of these programs does exactly what the Perl program (code segment) above does. With PHP, if Ajax used POST to send the query string, then at the server, PHP will have the name/value pairs of the query string in an associative array, called $_POST. This is an internal PHP array and it is globally accessible. An associative array consists of keys with corresponding values. For the query string name/value pairs, the $_POST array keys are names, while the corresponding array values are query string values. The following PHP code is for the POST method:

<?php
$value = $_POST["fname"];
echo $value
?>

This is a PHP executable file whose name has to be in the URL of the Ajax code at the client. There are two lines in the code. The first line uses the name, "fname" as key of the $_POST associative array to obtain the value, "John". This value is assigned to the variable, $value. Remember, the associative array will always hold the query string sent. The second line in the code sends the value "John" into the stream of the connection.

The following code does the same thing, but for the GET method. Here PHP has the $_GET associative array to hold the name/value pairs of the query string, sent by Ajax, using the GET method.

<?php
$value = $_GET["fname"];
echo $value
?>

Conclusion
At the server there is no new standard or technology for Ajax. All you have to know is how a language gets the data from the query string sent and how it sends text (any string) back into a connection stream initiated from the client. You can use any language for this: C++, Borland Delphi, Visual Basic.net etc. I have used only perl and PHP for illustration.

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