xhr_intercept

function xhr(xhrMethodName, appendedFunc) {
  (function(xhrMethod) {
    XMLHttpRequest.prototype[xhrMethodName] = function(data) {
      appendedFunc(data);
      xhrMethod.call(this.data);
    };
  })(XMLHttpRequest.prototype[xhrMethodName]);
}
// xhr('send', function(d) {console.log(d)});