runtime.onConnect
当使用扩展处理或 content script 建立连接时触发。
Syntax
js
browser.runtime.onConnect.addListener(listener); browser.runtime.onConnect.removeListener(listener); browser.runtime.onConnect.hasListener(listener); 事件包含三个函数：
addListener(callback)-
为此事件添加监听器。
removeListener(listener)-
停止监听此事件。
listener参数为需要移除的监听器。 hasListener(listener)-
检查是否已为此事件注册了
listener。如果正在监听，则返回true，否则返回false。
addListener 语法
参数
function-
A callback function that will be called when this event occurs. The function will be passed the following arguments:
port-
A
runtime.Portobject connecting the current script to the other context it is connecting to.
Browser compatibility
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Examples
This content script:
- connects to the background script, and stores the
Portin a variablemyPort - listens for messages on
myPort, and logs them - sends messages to the background script, using
myPort, when the user clicks the document
js
// content-script.js var myPort = browser.runtime.connect({ name: "port-from-cs" }); myPort.postMessage({ greeting: "hello from content script" }); myPort.onMessage.addListener(function (m) { console.log("In content script, received message from background script: "); console.log(m.greeting); }); document.body.addEventListener("click", function () { myPort.postMessage({ greeting: "they clicked the page!" }); }); The corresponding background script:
-
listens for connection attempts from the content script
-
when it receives a connection attempt:
- stores the port in a variable named
portFromCS - sends the content script a message using the port
- starts listening to messages received on the port, and logs them
- stores the port in a variable named
-
sends messages to the content script, using
portFromCS, when the user clicks the extension's browser action
js
// background-script.js var portFromCS; function connected(p) { portFromCS = p; portFromCS.postMessage({ greeting: "hi there content script!" }); portFromCS.onMessage.addListener(function (m) { console.log("In background script, received message from content script"); console.log(m.greeting); }); } browser.runtime.onConnect.addListener(connected); browser.browserAction.onClicked.addListener(function () { portFromCS.postMessage({ greeting: "they clicked the button!" }); }); 备注： This API is based on Chromium's chrome.runtime API. This documentation is derived from runtime.json in the Chromium code.