chrome extension to read post request data - google-chrome-extension

Question

I am trying to read json of post request using Chrome Extension. So i have created a extension with following code:-
menifest.json file:-
{
"name": "numera name",
"version": "1.0",
"description": "numera",
"manifest_version": 2,
"content_scripts": [
{
"matches": ["<all_urls>"],
"run_at": "document_start",
"js": ["contentScript.js"]
}
],
"permissions": [
"activeTab",
"tabs"
]
}
contentScript.js
function interceptData() {
var xhrOverrideScript = document.createElement('script');
xhrOverrideScript.type = 'text/javascript';
xhrOverrideScript.innerHTML = '
(function() {
var XHR = XMLHttpRequest.prototype;
var send = XHR.send;
var open = XHR.open;
XHR.open = function(method, url) {
this.url = url; // the request url
return open.apply(this, arguments);
}
XHR.send = function() {
this.addEventListener('load', function() {
if (this.url.includes('WaitForResponsesData')) {
var dataDOMElement = document.createElement('div');
dataDOMElement.id = '__interceptedData';
dataDOMElement.innerText = this.response;
console.log(this.response);
dataDOMElement.style.height = 0;
//dataDOMElement.style.overflow = 'hidden';
document.body.appendChild(dataDOMElement);
}
});
return send.apply(this, arguments);
};
})();'
document.head.prepend(xhrOverrideScript);
}
function checkForDOM() {
if (document.body && document.head) {
interceptData();
} else {
requestIdleCallback(checkForDOM);
}
}
requestIdleCallback(checkForDOM);
function scrapeData() {
var responseContainingEle = document.getElementById('__interceptedData');
if (responseContainingEle) {
var response = JSON.parse(responseContainingEle.innerHTML);
} else {
requestIdleCallback(scrapeData);
}
}
requestIdleCallback(scrapeData);
But I am not sure why this code is not working i have added console log and alert as well not no luck,
Also i have tried to search __interceptedData ID in page HTML but that is also not there.
I followed this URL https://medium.com/better-programming/chrome-extension-intercepting-and-reading-the-body-of-http-requests-dd9ebdf2348b
please help me out from this