如何在javascript中动态加载gtag.js（Google Analytics）

Question

当用户不想获取 cookie 时，我试图在 javascript 中阻止谷歌分析。

if (want_cookie != "no"){
   /* load google analytics script */
 }

但是我没有找到如何在javascript中加载这个脚本......

<script async src="https://www.googletagmanager.com/gtag/js?id=UA-XXXXXX"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-XXXXXX');
</script>

Answer 1

尝试这样的事情：

    if (want_cookie != "no"){
        var newScript = document.createElement("script");
            newScript.type = "text/javascript";
            newScript.setAttribute("async", "true");
            newScript.setAttribute("src", "https://www.googletagmanager.com/gtag/js?id=UA-XXXXXX");
            document.documentElement.firstChild.appendChild(newScript);
}

所以我所做的是在检查用户是否同意 cookie 后动态创建脚本元素并将其附加到页面。

Answer 2

在已接受的答案的基础上，我像这样实现了它：

HTML：

<div id="declineButton">Decline</div>
<div id="acceptButton">Accept</div>

JS 拒绝：

declineButton.addEventListener("click", () => {
  window["ga-disable-G-XXXX"] = true; // replace G-XXXX with your id
});

接受JS：

acceptButton.addEventListener("click", () => {
  window["ga-disable-G-XXXX"] = false; // replace G-XXXX with your id
  appendScriptToHead();
  executeGoogleAnalyticsScript();
});

function appendScriptToHead() {
  const script = document.createElement("script");
  script.type = "text/javascript";
  script.async = true;
  script.src = "https://www.googletagmanager.com/gtag/js?id=G-XXXX"; // replace G-XXXX with your ID
  document.head.appendChild(script);
}

function executeGoogleAnalyticsScript() {
  window.dataLayer = window.dataLayer || [];
  function gtag() {
    dataLayer.push(arguments);
  }
  gtag("js", new Date());
  gtag("config", "G-XXXX"); // replace G-XXXX with your id
}

注意： 根据 documentation，我们必须确保在执行

gtag()

之前完成禁用（设置窗口属性）。