Hi hermit23,
Here's a short but complete example of a self-contained CGI script that will query the server and display the data points it gets back.
It makes use of Javascript/jQuery, and calls back to the server once, using Ajax to get the data points, which it then displays to page. You can, of course, modify the subroutine "server_side_ajax()" to have more meaningful points than the random ones my script generates. Plus, you can do something more fun with the points in the javascript function "done_query" than just print them to the page.
Of course, let us know if you have any questions.
Update: And if you were only asking about how not to use '$', pay special attention to the line "var J = jQuery.noConflict();" which enables the magic letting you refer to jQuery with 'J' (or whatever else you like) instead of '$'.
#!/usr/bin/perl
###############
## Libraries ##
###############
use strict;
use warnings;
use JSON;
##################
## User-defined ##
##################
# This is a link to Google's publicly-available jQuery library
my $jquery = "ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js
+";
##################
## Main Program ##
##################
my $this_prog = $ENV{'REQUEST_URI'};
my $h_param = cgi_params();
if (exists $h_param->{'ajax'}) {
# If 'ajax' was sent in the URL, it's the client communicating
# with the Server via Ajax. See function ajax_query_server(),
# which initiates this. You could also put '?ajax' in the URL
# query to see the data results directly.
##
server_side_ajax();
} else {
# If the URL doesn't contain the key 'ajax', we display the HTML
# page normally.
##
print "Content-type: text/html\n\n";
print_javascript();
print_html_page();
}
#################
## Subroutines ##
#################
sub cgi_params {
my $query = $ENV{'QUERY_STRING'} || 0;
$query or return { };
my $h_params = { };
foreach my $key (split('&', $query)) {
my $val = ($key =~ s/=(.*)$//)? $1: undef;
$h_params->{$key} = $val;
}
return $h_params;
}
sub server_side_ajax {
# Calculate data somehow
my $a_data = [ ];
my $npoints = 16;
# For the sake of example, just randomize it for now
for (my $i = 0; $i < $npoints; $i++) {
my ($x, $y) = (int(rand(100)), int(rand(100)));
push @$a_data, [ $x, $y ];
}
my $h_json = { 'data' => $a_data };
# Print the JSON header and data
print "Content-type: application/json\n\n";
print to_json($h_json);
exit;
}
sub print_javascript {
# Send the jQuery/Javascript code to the browser
print qq{
<head>
<script src="https://$jquery"></script>
<script>
// I prefer 'J' to '$' for jQuery within Perl
var J = jQuery.noConflict();
J(function() { ajax_query_server() });
// Here the browser talks to the server
function ajax_query_server() {
J.ajax({
url: "$this_prog",
dataType: 'json',
data: { ajax: 1 },
success: function(json) { done_query(json); }
});
}
// Here the browser gets data back from the server
function done_query(json) {
var a_points = json['data'];
for (var i = 0; i < a_points.length; i++) {
var x = a_points[i][0];
var y = a_points[i][1];
var text = "Point "+(i+1)+": ("+x+","+y+")\\n";
J('#data').append(text);
}
}
</script>
</head>
};
}
sub print_html_page {
# Here's where the HTML body gets printed
print qq{
<body style="background:peachpuff">
<h3> Ajax Data Example </h3>
<pre id="data"></pre>
</body>
};
}
say
substr+lc crypt(qw $i3 SI$),4,5
