1-It runs but when the cgi recive red as param it prints out the value before any other things. Why?

Don't know what you mean by this, but you have two typos in your code where you forget to open and close your quotes.

2-Is correct the $|=1; line ? When I really need this unbuffered stuff ?

Yes this switches off buffering which is often a good idea. See Suffering from Buffering for details

3-Can I use only cgi file to print out html output? I prefer the syntax of the module instead of the html one.

No you can just use print if you want, see the example below.

4-Why Ovid never use $|=1; ?

He does ;-) But he knows when it is needed....

Using strict and warnings will save you a lot of grief, See Use strict warnings and diagnostics or die

-T taint mode protects you from allowing CGI input to do nasty stuff to your file system. You set it up a little different on IIS or you will get a too late for -T error. See http://gunther.web66.com/FAQS/taintmode.html

#!perl

use strict;      # stop typos and other errors causing grief
use warnings;    # stop CGI newbie making silly errors
use diagnostics; # explain warnings to CGI newbie

use CGI;
my $q = new CGI;

print $q->header;

$q->param('calore') ||= '';  # ensure param initialized before using e
+q

if ( $q->param('calore') eq 'red' ) {
     print '<h3>You said red</h3>';
} else {
     print '<h3>You did not say red</h3>';
}
[download]

cheers

tachyon

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