diff --git a/modules/appnexusBidAdapter.js b/modules/appnexusBidAdapter.js
index cf73b69991f..948e1c31b17 100644
--- a/modules/appnexusBidAdapter.js
+++ b/modules/appnexusBidAdapter.js
@@ -10,6 +10,7 @@ import {
   getMaxValueFromArray,
   getMinValueFromArray,
   getParameterByName,
+  getUniqueIdentifierStr,
   isArray,
   isArrayOfNums,
   isEmpty,
@@ -444,16 +445,6 @@ export const spec = {
     }
 
     return params;
-  },
-
-  /**
-   * Add element selector to javascript tracker to improve native viewability
-   * @param {Bid} bid
-   */
-  onBidWon: function (bid) {
-    if (FEATURES.NATIVE && bid.native) {
-      reloadViewabilityScriptWithCorrectParameters(bid);
-    }
   }
 };
 
@@ -467,58 +458,9 @@ function deleteValues(keyPairObj) {
   }
 }
 
-function reloadViewabilityScriptWithCorrectParameters(bid) {
-  let viewJsPayload = getAppnexusViewabilityScriptFromJsTrackers(bid.native.javascriptTrackers);
-
-  if (viewJsPayload) {
-    let prebidParams = 'pbjs_adid=' + bid.adId + ';pbjs_auc=' + bid.adUnitCode;
-
-    let jsTrackerSrc = getViewabilityScriptUrlFromPayload(viewJsPayload);
-
-    let newJsTrackerSrc = jsTrackerSrc.replace('dom_id=%native_dom_id%', prebidParams);
-
-    // find iframe containing script tag
-    let frameArray = document.getElementsByTagName('iframe');
-
-    // boolean var to modify only one script. That way if there are muliple scripts,
-    // they won't all point to the same creative.
-    let modifiedAScript = false;
-
-    // first, loop on all ifames
-    for (let i = 0; i < frameArray.length && !modifiedAScript; i++) {
-      let currentFrame = frameArray[i];
-      try {
-        // IE-compatible, see https://stackoverflow.com/a/3999191/2112089
-        let nestedDoc = currentFrame.contentDocument || currentFrame.contentWindow.document;
-
-        if (nestedDoc) {
-          // if the doc is present, we look for our jstracker
-          let scriptArray = nestedDoc.getElementsByTagName('script');
-          for (let j = 0; j < scriptArray.length && !modifiedAScript; j++) {
-            let currentScript = scriptArray[j];
-            if (currentScript.getAttribute('data-src') == jsTrackerSrc) {
-              currentScript.setAttribute('src', newJsTrackerSrc);
-              currentScript.setAttribute('data-src', '');
-              if (currentScript.removeAttribute) {
-                currentScript.removeAttribute('data-src');
-              }
-              modifiedAScript = true;
-            }
-          }
-        }
-      } catch (exception) {
-        // trying to access a cross-domain iframe raises a SecurityError
-        // this is expected and ignored
-        if (!(exception instanceof DOMException && exception.name === 'SecurityError')) {
-          // all other cases are raised again to be treated by the calling function
-          throw exception;
-        }
-      }
-    }
-  }
-}
-
 function strIsAppnexusViewabilityScript(str) {
+  if (!str || str === '') return false;
+
   let regexMatchUrlStart = str.match(VIEWABILITY_URL_START);
   let viewUrlStartInStr = regexMatchUrlStart != null && regexMatchUrlStart.length >= 1;
 
@@ -528,30 +470,6 @@ function strIsAppnexusViewabilityScript(str) {
   return str.startsWith(SCRIPT_TAG_START) && fileNameInStr && viewUrlStartInStr;
 }
 
-function getAppnexusViewabilityScriptFromJsTrackers(jsTrackerArray) {
-  let viewJsPayload;
-  if (isStr(jsTrackerArray) && strIsAppnexusViewabilityScript(jsTrackerArray)) {
-    viewJsPayload = jsTrackerArray;
-  } else if (isArray(jsTrackerArray)) {
-    for (let i = 0; i < jsTrackerArray.length; i++) {
-      let currentJsTracker = jsTrackerArray[i];
-      if (strIsAppnexusViewabilityScript(currentJsTracker)) {
-        viewJsPayload = currentJsTracker;
-      }
-    }
-  }
-  return viewJsPayload;
-}
-
-function getViewabilityScriptUrlFromPayload(viewJsPayload) {
-  // extracting the content of the src attribute
-  // -> substring between src=" and "
-  let indexOfFirstQuote = viewJsPayload.indexOf('src="') + 5; // offset of 5: the length of 'src=' + 1
-  let indexOfSecondQuote = viewJsPayload.indexOf('"', indexOfFirstQuote);
-  let jsTrackerSrc = viewJsPayload.substring(indexOfFirstQuote, indexOfSecondQuote);
-  return jsTrackerSrc;
-}
-
 function formatRequest(payload, bidderRequest) {
   let request = [];
   let options = {
@@ -633,7 +551,9 @@ function newRenderer(adUnitCode, rtbBid, rendererOptions = {}) {
  */
 function newBid(serverBid, rtbBid, bidderRequest) {
   const bidRequest = getBidRequest(serverBid.uuid, [bidderRequest]);
+  const adId = getUniqueIdentifierStr();
   const bid = {
+    adId: adId,
     requestId: serverBid.uuid,
     cpm: rtbBid.cpm,
     creativeId: rtbBid.creative_id,
@@ -721,20 +641,20 @@ function newBid(serverBid, rtbBid, bidderRequest) {
     }
   } else if (FEATURES.NATIVE && rtbBid.rtb[NATIVE]) {
     const nativeAd = rtbBid.rtb[NATIVE];
+    let viewScript;
 
-    // setting up the jsTracker:
-    // we put it as a data-src attribute so that the tracker isn't called
-    // until we have the adId (see onBidWon)
-    let jsTrackerDisarmed = rtbBid.viewability.config.replace('src=', 'data-src=');
+    if (strIsAppnexusViewabilityScript(rtbBid.viewability.config)) {
+      let prebidParams = 'pbjs_adid=' + adId + ';pbjs_auc=' + bidRequest.adUnitCode;
+      viewScript = rtbBid.viewability.config.replace('dom_id=%native_dom_id%', prebidParams);
+    }
 
     let jsTrackers = nativeAd.javascript_trackers;
-
     if (jsTrackers == undefined) {
-      jsTrackers = jsTrackerDisarmed;
+      jsTrackers = viewScript;
     } else if (isStr(jsTrackers)) {
-      jsTrackers = [jsTrackers, jsTrackerDisarmed];
+      jsTrackers = [jsTrackers, viewScript];
     } else {
-      jsTrackers.push(jsTrackerDisarmed);
+      jsTrackers.push(viewScript);
     }
 
     bid[NATIVE] = {
diff --git a/test/spec/modules/appnexusBidAdapter_spec.js b/test/spec/modules/appnexusBidAdapter_spec.js
index 5ec481e140c..6f00d851a94 100644
--- a/test/spec/modules/appnexusBidAdapter_spec.js
+++ b/test/spec/modules/appnexusBidAdapter_spec.js
@@ -1195,6 +1195,7 @@ describe('AppNexusAdapter', function () {
     it('should get correct bid response', function () {
       let expectedResponse = [
         {
+          'adId': '3a1f23123e',
           'requestId': '3db3773286ee59',
           'cpm': 0.5,
           'creativeId': 29681110,
diff --git a/test/spec/modules/big-richmediaBidAdapter_spec.js b/test/spec/modules/big-richmediaBidAdapter_spec.js
index 1e97e1ac1d7..b2ee0725d49 100644
--- a/test/spec/modules/big-richmediaBidAdapter_spec.js
+++ b/test/spec/modules/big-richmediaBidAdapter_spec.js
@@ -190,6 +190,7 @@ describe('bigRichMediaAdapterTests', function () {
     it('should get correct bid response', function () {
       const expectedResponse = [
         {
+          'adId': '3a1f23123e',
           'requestId': '3db3773286ee59',
           'cpm': 0.5,
           'creativeId': 29681110,