尝试根据某个条件填充图像源时未捕获TypeError

Question

我正在尝试根据情况更改http/https的链接。正在运行的代码如下

<script>
  var _comscore = _comscore || [];
  _comscore.push({ c1: "2", c2: "7109919" });
  (function () {
    var s = document.createElement("script"), el = document.getElementsByTagName("script")[0]; s.async = true;
    s.src = (document.location.protocol == "https:" ? "https://sb" : "http://b") + ".scorecardresearch.com/beacon.js";
    el.parentNode.insertBefore(s, el);
  })();
</script>
<noscript>
  <img src="http://b.scorecardresearch.com/p?c1=2&c2=7109919&cv=2.0&cj=1" />
</noscript>

我尝试做的是更改“noscript”部分。在'noscript‘部分，代码需要根据http/https协议进行更改；

如果协议是http，则链接需要以'b.scorecardresearch.com‘开头；如果协议是https，则链接需要以'sb.scorecardresearch.com’开头

这是我的代码，我试图像这样填充img的源代码。

{# Comscore Tag #}
<noscript>
  <img id="iScorecardresearch" src="" />
</noscript>

<script>
  var _comscore = _comscore || [];
  _comscore.push({ c1: "2", c2: "7109919" });
  (function () {
    var s = document.createElement("script"), el = document.getElementsByTagName("script")[0]; s.async = true;
    document.getElementById("iScorecardresearch").src = (document.location.protocol == "https:" ? "https://sb" : "http://b") + ".scorecardresearch.com/p?c1=2&c2=7109919&cv=2.0&cj=1";
    s.src = (document.location.protocol == "https:" ? "https://sb" : "http://b") + ".scorecardresearch.com/beacon.js";
    el.parentNode.insertBefore(s, el);
    var ns = document.createElement("noscript"), elns = document.getElementsByTagName("noscript")[0];
  })();
</script> 

但是我得到一个错误，它是‘未捕获TypeError:无法设置属性'src’of null‘’

由于我是新的前端和JavaScript，我被困在这个错误，任何人可以建议任何解决方案来解决这个错误？提前感谢

Answer 1

iScorecardresearch隐藏在noscript的内部。浏览器将无法访问它。