Chrome 扩展 background 与content_script 之间通信

content_script 向 background 发消息要用：chrome.runtime.sendMessage

        chrome.runtime.sendMessage({event: "xhr", data:option }, function (res) { //option.onload(res);//console.log(res);if (res.event == "xhr" && !res.err){option.onload(res);}});

background 接收消息：chrome.runtime.onMessage.addListener

chrome.runtime.onMessage.addListener(function (message, sender, sendResponse) {if (message.event == "copy") {//alert("copy detected");//return true;}sendResponse({});return true; 
});

background 向 content_script 发消息要用：chrome.tabs.sendMessage

            chrome.tabs.query({ active: true, currentWindow: true }, function(tabs) {if (tabs && tabs.length > 0) {const activeTab = tabs[0];console.log('当前活动标签页的是：', activeTab);try {chrome.tabs.sendMessage(activeTab.id, {'evt':'mediaUrl','data':mediaUrl }, function (res) { console.log(res);});} catch (error) {console.error(error.message);}}});

content_script 接收消息用：chrome.runtime.onMessage.addListener

和background中是一样的，注意其中的 sendResponse({});

这一句很关键，接收到了就要给一个回应；