Store result of http request to variable

Hi I get problem to fetch content of web page. Please see my code below

var http = require('http');
var html = '';
var options = {
    host: 'dev.gunship.io',
    path: '/node.html'
};
callback = function(response) {
    response.on('data', function(chunk) {
        html += chunk;
    });
    response.on('end', function() {
        //console.log(html);
    });
};
http.request(options, callback).end();
console.log(html);

Why my console not log anything..? Thank you for any help