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Here's one way to do it: use strict;
use CGI qw(:standard);
print header(), start_html("Add Me");
print h1("Add Me");
if(param()) {
my $n1 = param('field1');
my $n2 = param('field2');
my $n3 = $n2 + $n1;
print p("$n1 + $n2 = <strong>$n3</strong>\n");
} else {
print hr(), start_form();
print p("First Number:", textfield("field1"));
print p("Second Number:", textfield("field2"));
print p(submit("add"), reset("clear"));
print end_form(), hr();
}
print end_html(); If there's no input, simply generate a form with two textfields (using the textfield method). If there is input, we add the two fields together and print the result. Here's one way to do it: use strict;
use CGI qw(:standard);
print header(), start_html("Browser Detective");
print h1("Browser Detective"), hr();
my $browser = $ENV{'HTTP_USER_AGENT'};
$_ = $browser;
BROWSER:{
if (/msie/i) {
msie($_);
} elsif (/mozilla/i) {
netscape($_);
} elsif (/lynx/i) {
lynx($_);
} else {
default($_);
}
}
print end_html();
sub msie{
print p("Internet Explorer: @_. Good Choice\n");
}
sub netscape {
print p("Netscape: @_. Good Choice\n");
}
sub lynx {
print p("Lynx: @_. Shudder...");
}
sub default {
print p("What the heck is a @_?");
} The key here is checking the environment for the HTTP_USER_AGENT variable. Although this isn't implemented by every server, many of them do set it. This is a good way to generate content geared to the features of a particular browser. Note that we're just doing some basic string matching (case insensitive) to see what they're using (nothing too fancy).
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