Chrome扩展程序browserAction无效

Question

我无法将消息从后台页面传递到内容页面，下面是我的代码。我尝试从扩展库中下载代码示例，但即使在此之后也无法正常工作，

background.js：

chrome.browserAction.onClicked.addListener(function (tab) {
    chrome.tabs.sendMessage(tab.id, {
        greeting: "hello"
    }, function (response) {
        alert(JSON.stringify(response, null, 4));
    });
});

content.js：

chrome.runtime.onMessage.addListener(function (request, sender, sendResponse) {
    sendResponse({farewell: "goodbye"});
});

的manifest.json：

{
    "name": "Test Screenshot Extension",
    "version": "1.3",
    "description": "Demonstrate screenshot functionality in the chrome.tabs api.",
    "background": {
        "persistent": false,
        "scripts": ["background.js"]
    },
    "icons": {
        "128": "icon-128.png",
        "48": "icon-48.png"
    },
    "browser_action": {
        "default_icon": "icon-128.png",
        "default_title": "Take a screen shot!"
    },
    "permissions": ["tabs"],
    "manifest_version": 2
}

警告线（JSON.stringify（响应，空，4））; 警告＆＃34;未定义＆＃34;