Ajax

/* 
    var url = '//media.ao.com/cdnbundle/client/4.0.90.0/bundled/BTS/css/MasterStructure.css';
    var ajax = new XMLHttpRequest();
    ajax.onreadystatechange = function() {
        if(this.readyState === 4 && this.status === 200) {
          console.log(this.responseText);
        }
    };
    ajax.open('GET', url, true);
    ajax.send();

    Convert (only) the above into a new API
        Do it in anyway you see fit but:
        -   Give it a GET method
        -   Make it Promise based

*/

var link = '//media.ao.com/cdnbundle/client/4.0.90.0/bundled/BTS/css/MasterStructure.css';
var Ajax = (function() {
    const ajax = new XMLHttpRequest();
    function request(method, url) {
        return new Promise(function(res, rej) {
            ajax.onreadystatechange = function() {
                const { readyState, status, responseText } = this;
                if(readyState === 4) {
                    if(status === 200) {
                        res(responseText);
                    }
                    else {
                        rej(status);
                    }
                }
            };
            ajax.open(method, url, true);
            ajax.send();
        })
    }
    function get(url) {
        return request('GET', url);
    }
    return { get };
})();

Ajax
    .get(link)
    .then(function(text) {
        console.log('success', text);
    })
    .catch(function(error) {
        console.log('error', error);
    });