ajax-vanilla-js.js

/* http://idiallo.com/javascript/ajax-without-jquery */

var url = "http://jsonplaceholder.typicode.com/posts";

var Ajax = {
  xhr : null,
  request : function (url, method, data, success, failure) {
    if (!this.xhr) {
        this.xhr = new XMLHttpRequest();
    }
    var self = this.xhr;

    self.onreadystatechange = function () {
      if (self.readyState === 4 && self.status === 200) {
        // the request is complete, parse data and call callback
        var response = JSON.parse(self.responseText);
        success(response);
      }
      else if (self.readyState === 4) { // something went wrong but complete
        failure();
      }
    };
    this.xhr.open(method, url, true);
    this.xhr.send();
  }
};

Ajax.request(url, "GET", null, function(data) {
    console.log("success");
}, function() {
    console.log("failed");
});