嘗試在內(nèi)容腳本和后臺(tái)腳本之間進(jìn)行通信時(shí)，出現(xiàn)以下錯(cuò)誤：Port error: Could not establish connection. Receiving end does not exist.Error in event handler for 'undefined': Cannot read property 'message' of undefined       TypeError: Cannot read property 'message' of undefinedbackground.jsfunction onRequest(request, sender, callbackFunction) {    console.log("Me (BS) became this Message:" + request.message);    sendResponse({message: request.message})};chrome.extension.onRequest.addListener(onRequest);streamcloud.jsfunction contactBackground(nachricht){    chrome.extension.sendMessage({message: nachricht}, function(response) {        console.log("The Background Script got the following Message: " + response.message);    });}和我的manifest.json{  "name": "InstantWatch - Dev",  "manifest_version": 2,  "version": "0.7",  "permissions": ["tabs", "http://*/", "https://*/"],  "background": {    "scripts": ["background.js"]  },    "browser_action": {    "default_title": "InstantWatch",    "default_icon" : "icon.ico"  },  "content_scripts": [    {      "matches": ["http://*/*", "http://*/*"],      "js": ["jquery.js", "streamcloud.js"]    }  ]}我找到了添加一個(gè)background_page：“ background.html”和一個(gè)空白background.html的解決方案，但是由于manifest_version：2后不支持background_page，所以我不能使用它。