chrome.runtime.onMessage.addListener在內容腳本中不起作用

Question

在Chrome擴展中，我嘗試從後臺腳本向內容腳本發送消息。內容腳本中沒有收到消息。哪裏出錯？這裏的background.js

function createAlarm() { 
    chrome.alarms.create('bookcab', { 
      periodInMinutes: 1 
    }); 
} 

chrome.alarms.onAlarm.addListener(function(alarm) { 
    if (alarm.name === 'bookcab') { 
     var url = 'http://cab/'; 
     chrome.tabs.create({ url:url, active: true }); 
     chrome.tabs.query({active:true}, function(tabs){ 
      chrome.tabs.sendMessage(tabs[0].id, {"message": "sample_msg"}); 
     }); 
    } 
}); 

createAlarm(); 

而且content_script.js具有下面的代碼，

chrome.runtime.onMessage.addListener(
    function(request,sender,sendresponse) { 
    if(request.message === "sample_msg") { 
     console.log('message from content script');      
    } 
    } 
); 

這裏的manifest.json的，如果它的事項

{ 
    "manifest_version": 2, 
    "name":"bookcab", 
    "version":"0.1", 
    "background": { 
     "scripts":["background.js"] 
    }, 
    "permissions": [ 
     "alarms", 
     "tabs" 
    ], 
    "content_scripts": [{ 
     "matches":["<all_urls>"], 
     "js": ["content_script.js"], 
     "run_at" : "document_end" 
    }] 
} 

Answer 1

我已經包括了一個標籤負載在將消息發送到內容腳本之前完成。

等待選項卡以滿載

chrome.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {   
    if (changeInfo.status == 'complete') { 
     chrome.tabs.query({active: true}, function(tabs){ 
     chrome.tabs.sendMessage(tabs[0].id, {"message": "sample_msg"}); 
     } 
    } 
});