CODE:

use XML::Simple;

my $app = sub {
    my $xml = +{
        Message => [
            "Test Message"
        ],
    };

    return [
        200,
        [ContentType => "text/xml"],
        [XMLout($xml, RootName => "root", XMLDecl => 1)],
    ];
}

CODE:

var button = document.getElementById('ajax');
button.onclick = function() {
    var xml = new XMLHttpRequest();
    xml.onreadystatechange = function() {
        if (xml.readyState == 4 && xml.status == 200) {
            var result = document.getElementById('result');
            result.value = xml.responseText;
        }
    };
    xml.open('GET', 'ここにアドレス');
    xml.send(null);
};

CODE:

    
        Test