CODEWITHSUNDEEP
javascriptgoogle-chrome-extension
Cyrillou
Cyrillou

Reputation: 161

Highlight current DOM element in Chrome Extension using DebuggerApi

I'm currently building an extension for chrome (I'm a beginner) and looking for some help to some one issue. The flow of the extension is the following:

After step 2 I attach a new Debugger instance to the tab. it seems like you can do this action either in background.js or content-script.js. Both work so my question is which one makes more sense. I'd say content-script because it doesn't interact directly with the browser but only with my extension. Am I right?

Second question is when using the DebuggerAPI I need to send command using the DevTools Protocol Viewer. I guess the command I must send to interact with my DOM element sit under this category (https://chromedevtools.github.io/devtools-protocol/tot/DOM). Most of the command requires a NodeId parameter. My question is how would I get this NodeId when the mouse cursor is over it. I have the following event in my content-script

chrome.runtime.onMessage.addListener(function(msg, sender){
    if(msg == "togglePanel"){
        togglePanel();
    } else if (msg == "startCaptureElement") {
      console.log("- Content-Script.js: Add Mouse Listener");
      document.addEventListener('mouseover', captureEvent);
    } else if (msg == "stopCaptureElement") {
      console.log("- Content-Script.js: Remove Mouse Listener");
      document.removeEventListener('mouseover', captureEvent);
    }
});

function captureEvent(el) {
    //console.log("- Content-Script.js: It's moving");
    console.log(el);
    chrome.runtime.sendMessage("highlightElement");
}

In my background.js script

chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    console.log(sender);

    if (request == "startCaptureElement") {
      console.log("- Background.js: Attach the debugger");
      chrome.debugger.attach({tabId: sender.tab.id}, "1.0");
      chrome.tabs.sendMessage(sender.tab.id, "startCaptureElement");
    } else if (request == "stopCaptureElement") {
      console.log("- Background.js: Detach the debugger");
      chrome.debugger.detach({tabId: sender.tab.id});
      chrome.tabs.sendMessage(sender.tab.id, "stopCaptureElement");
    } else if (request == "highlightElement") {
      console.log("- Background.js: Highlight Element");
      chrome.debugger.sendCommand({tabId: sender.tab.id}, "DOM.enable", {});
      chrome.debugger.sendCommand({tabId: sender.tab.id}, "Overlay.inspectNodeRequested", {}, function(result) {
        console.log(result);
      });
    }
  }
);

I found the similar question here How to highlight elements in a Chrome Extension similar to how DevTools does it? but the code provided confused me a little bit.

Thanks for your help

Upvotes: 2

Views: 2878

Answers (1)

yongjin
yongjin

Reputation: 41

"Overlay.inspectNodeRequested" is an event that should be listened to. you can call "Overlay.setInspectMode" to select a node.

background.js:

var version = "1.0";

//show popup page while click icon
chrome.browserAction.onClicked.addListener(function(tab) {
    chrome.debugger.attach({tabId:tab.id}, version,
        onAttach.bind(null, tab.id));
});

function onAttach(tabId) {
    if (chrome.runtime.lastError) {
        alert(chrome.runtime.lastError.message);
        return;
    }

    chrome.windows.create(
        {url: "headers.html?" + tabId, type: "popup", width: 800, height: 600});
}

headers.html:

<html>
<head>
  <meta charset="utf-8">
  <script src="headers.js"></script>
</head>
<body>
  <div id="container">
    <button id="btn_inspect">select node</button>
  </div>
</body>
</html>

headers.js:

var tabId = parseInt(window.location.search.substring(1));

var hightCfg = {
  'showInfo': true, 'showStyles':true, 'contentColor':{r: 155, g: 11, b: 239, a: 0.7}
}

//listen events when page is loaded
window.addEventListener("load", function() {
  chrome.debugger.sendCommand({tabId:tabId}, "DOM.enable");
  chrome.debugger.sendCommand({tabId:tabId}, "Overlay.enable");
  chrome.debugger.onEvent.addListener(onEvent);

  document.getElementById('btn_inspect').addEventListener('click', function(){
    chrome.debugger.sendCommand({tabId:tabId}, "Overlay.setInspectMode", 
      {'mode':'searchForNode', 'highlightConfig':hightCfg});
  });
});

window.addEventListener("unload", function() {
  chrome.debugger.detach({tabId:tabId});
});



var requests = {};

function onEvent(debuggeeId, message, params) {
  console.log('onEvent ...'+message);
  if (tabId != debuggeeId.tabId)
   return;

  if (message == "Network.inspectNodeRequested") {
    //do something..
  }
}

Upvotes: 4

Related Questions