Improvement/timeout xhr (prebid#1172)

* implement timeout on ajax requests

* missing semi-colon

Author: Matt Kendall

src/ajax.js

@@ -3,6 +3,7 @@ import {parse as parseURL, format as formatURL} from './url';
 var utils = require('./utils');
 
 const XHR_DONE = 4;
+let _timeout = 3000;
 
 /**
  * Simple IE9+ and cross-browser ajax request function
@@ -13,6 +14,9 @@ const XHR_DONE = 4;
  * @param data mixed data
  * @param options object
  */
+export function setAjaxTimeout(timeout) {
+  _timeout = timeout;
+}
 
 export function ajax(url, callback, data, options = {}) {
   try {
@@ -42,6 +46,7 @@ export function ajax(url, callback, data, options = {}) {
       }
     }
 
+    x.timeout = _timeout;
     if (useXDomainRequest) {
       x = new window.XDomainRequest();
       x.onload = function () {

src/prebid.js

@@ -10,6 +10,7 @@ import { isValidePriceConfig } from './cpmBucketManager';
 import { listenMessagesFromCreative } from './secureCreatives';
 import { syncCookies } from 'src/cookie.js';
 import { loadScript } from './adloader';
+import { setAjaxTimeout } from './ajax';
 
 
 var $$PREBID_GLOBAL$$ = getGlobal();
@@ -455,6 +456,7 @@ $$PREBID_GLOBAL$$.requestBids = function ({ bidsBackHandler, timeout, adUnits, a
   const timedOut = true;
   const timeoutCallback = bidmanager.executeCallback.bind(bidmanager, timedOut);
   const timer = setTimeout(timeoutCallback, cbTimeout);
+  setAjaxTimeout(cbTimeout);
   if (typeof bidsBackHandler === objectType_function) {
     bidmanager.addOneTimeCallback(bidsBackHandler, timer);
   }