javascript - How to Access / Read any Text / Tag Value from the Webpage using Chrome Extension -

i writing first chrome plugin , want text present on current webpage , show alert when click extension. lets using any webpage on www.google.com after search query, google shows "about 1,21,00,00,000 results (0.39 seconds) " . want show text alert when execute plugin. doing.

here manifest.json using

{   "manifest_version": 2,  "name": "getting started example", "description": "this extension shows google image search result current page", "version": "1.0",  "background": {   "persistent": false,   "scripts": ["background.js"] },  "content_scripts": [{ "matches": ["*://*.google.com/*"], "js": ["content.js"] }],  "browser_action": { "default_icon": "icon.png", "default_popup": "popup.html" },  "permissions": [ "activetab" ] } 

here popup.js

document.addeventlistener('domcontentloaded', function() { document.getelementbyid("checkpage").addeventlistener("click", handler); });`  function handler() { var = document.getelementbyid("resultstats"); alert(a.innertext);  // or alert(a.innerhtml); } 

here content.js

// listen messages chrome.runtime.onmessage.addlistener(function (msg, sender, sendresponse) { // if received message has expected format... if (msg.text === 'report_back') {     // call specified callback, passing     // web-page's dom content argument     sendresponse(document.all[0].outerhtml); } }); 

here background.js

var urlregex = /^https?:\/\/(?:[^./?#]+\.)?google\.com/;  // function use callback function dostuffwithdom(domcontent) {     console.log('i received following dom content:\n' + domcontent); }  // when browser-action button clicked... chrome.browseraction.onclicked.addlistener(function (tab) {     // ...check url of active tab against our pattern and...     if (urlregex.test(tab.url)) {         // ...if matches, send message specifying callback         chrome.tabs.sendmessage(tab.id, {text: 'report_back'}, dostuffwithdom);     } }); 

1) run content scrip after document ready ** check "run_at"

"content_scripts": [{      "run_at": "document_idle",      "matches"["*://*.google.com/*"],      "js": ["content.js"] }], 

2) on click of extension make js run( popup js). popup js has access ( open page document)

 // function use callback     function dostuffwithdom() {     //console.log('i received following dom content:\n' + domcontent);     //get tabid when browser action clicked @ tabid = tab.id      chrome.tabs.executescript(tabid, {file: "js/popup.js"});     } 

3) in popup js simple can set alert

var = document.getelementbyid("resultstats"); alert(a.innertext);  // or alert(a.innerhtml);