帮助Chrome扩展消息传递 [英] Help with chrome extension message passing

问题描述

我试图从一个背景页面中获取一串值到我制作的Google Chrome扩展程序中的内容脚本。

I am trying to get a string of values from a background page to my content script in a Google Chrome extension I am making.

我遇到的问题是当我尝试获取内容脚本的值时，它不会执行。这是代码

The problem I am encountering is that when I try to get the value to the content script, it doesn't go. Here is the code

var list1 = "";
chrome.extension.sendRequest({action: 'list'}, function(response) {
      list1 = response.data;
   alert("hey from inside:" + list1 +":"+response.data);
});
alert(list1);

出现的第一个警告显示正确地说出嘿从里面和列表我想内容脚本有。但是，当我尝试提醒从请求外存储它的变量时，它不显示该列表。

The first alert that comes up shows properly saying "hey from inside" and the list I want the content script to have. But then, when I try to alert the variable that I stored it in from outside of that request, it doesn't show the list.

请帮助

推荐答案

大多数（如果不是全部）Chrome扩展API都是异步。当 sendRequest 被触发时，警报将被触发。在这种情况下，它将是一个空字符串。由于异步性质，您无法保证 list1 的交付。

Most (if not all) of the Chrome Extensions API are asynchronous. When your sendRequest gets fired, the alert will be fired. In this case it will be an empty string. You cannot guarantee the delivery of list1, because of this asynchronous nature.

现在，您可以重新构建代码，以便利用异步事件。例如：
$ b

content_script.js

Now, what you can do is re-architect your code so that you can take advantage of the asynchronous matter. For example:

chrome.extension.sendRequest({action: 'list'}, function(response) {
   onListReceived(response.data)
});

function onListReceived(list) {
  alert(list);
}

这篇关于帮助Chrome扩展消息传递的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！