检查嵌入标签是否存在 javascript

发布于 2025-01-04 05:18:01 字数 457 浏览 1 评论 0原文

如何检查我的 html 中是否存在嵌入标签。我已经通过 javascript 创建了这个标签

    soundEmbed = document.createElement("embed");
    soundEmbed.setAttribute("src", "notify.wav");
    soundEmbed.setAttribute("hidden", true);
    soundEmbed.setAttribute("autostart", true);
    soundEmbed.setAttribute("loop", false);
    document.body.appendChild(soundEmbed);

，但由于我使用自动刷新和appendChild，每次刷新时都会产生额外的声音。

使用appendChild，我想我有很多嵌入标签。我认为这可能是额外声音的原因。

原文

How can I check if embed tag exist in my html.
I've created this tag through javascript

    soundEmbed = document.createElement("embed");
    soundEmbed.setAttribute("src", "notify.wav");
    soundEmbed.setAttribute("hidden", true);
    soundEmbed.setAttribute("autostart", true);
    soundEmbed.setAttribute("loop", false);
    document.body.appendChild(soundEmbed);

but since I am using autorefresh and appendChild, every time it refresh it creates additional sound.

Using appendChild, I think I've got many embed tags. That's what I think maybe the cause of additional sound.

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昔梦 2025-01-11 05:18:01

在附加之前添加 soundEmbed.id = "__soundEmbed";。然后，用以下内容包围整个事物：

if( !document.getElementById("__soundEmbed")) {
    soundEmbed = ......;
    ......
}

Add soundEmbed.id = "__soundEmbed"; before appending. Then, surround the entire thing with:

if( !document.getElementById("__soundEmbed")) {
    soundEmbed = ......;
    ......
}

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花开浅夏 2025-01-11 05:18:01

您可以给元素一个 id 并首先检查它：

if (!document.getElementById('someId')) {
  var soundEmbed = document.createElement("embed");
  soundEmbed.setAttribute("src", "notify.wav");
  soundEmbed.setAttribute("hidden", true);
  soundEmbed.setAttribute("autostart", true);
  soundEmbed.setAttribute("loop", false);
  soundEmbed.setAttribute("id", 'someId');
  document.body.appendChild(soundEmbed);
}

或者，检查一个标志（因为 soundEmbed 似乎在其他地方定义，我们可以对其使用错误检查）：

if (!soundEmbed) {
  soundEmbed = document.createElement("embed");
  soundEmbed.setAttribute("src", "notify.wav");
  soundEmbed.setAttribute("hidden", true);
  soundEmbed.setAttribute("autostart", true);
  soundEmbed.setAttribute("loop", false);
  document.body.appendChild(soundEmbed);
}

You could give the element an id and check this first:

if (!document.getElementById('someId')) {
  var soundEmbed = document.createElement("embed");
  soundEmbed.setAttribute("src", "notify.wav");
  soundEmbed.setAttribute("hidden", true);
  soundEmbed.setAttribute("autostart", true);
  soundEmbed.setAttribute("loop", false);
  soundEmbed.setAttribute("id", 'someId');
  document.body.appendChild(soundEmbed);
}

Or alternatively, check against a flag (since soundEmbed seems to be defined elsewhere we can use a falsey check on it):

if (!soundEmbed) {
  soundEmbed = document.createElement("embed");
  soundEmbed.setAttribute("src", "notify.wav");
  soundEmbed.setAttribute("hidden", true);
  soundEmbed.setAttribute("autostart", true);
  soundEmbed.setAttribute("loop", false);
  document.body.appendChild(soundEmbed);
}

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