Documentï¼DOMContentLoaded äºä»¶

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addEventListener("DOMContentLoaded", (event) => {});

onDOMContentLoaded = (event) => {};

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document.addEventListener("DOMContentLoaded", (event) => {
  console.log("DOM å®å¨å è½½åè§£æ");
});

å»¶è¿ DOMContentLoaded

html

<script>
  document.addEventListener("DOMContentLoaded", (event) => {
    console.log("DOM å®å¨å è½½åè§£æ");
  });

  for (let i = 0; i < 1_000_000_000; i++);
  // è¿æ®µåæ¥èæ¬å°ä¼å»¶è¿ DOM è§£æï¼
  // æä»¥ DOMContentLoaded äºä»¶å°ä¼å»¶è¿æ§è¡ã
</script>

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function doSomething() {
  console.info("DOM å è½½äº");
}

if (document.readyState === "loading") {
  // æ¤æ¶å è½½å°æªå®æ
  document.addEventListener("DOMContentLoaded", doSomething);
} else {
  // `DOMContentLoaded` å·²ç»è¢«è§¦å
  doSomething();
}

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HTML

html

<div class="controls">
  <button id="reload" type="button">éæ°å è½½</button>
</div>

<div class="event-log">
  <label for="eventLog">äºä»¶æ¥å¿ï¼</label>
  <textarea
    readonly
    class="event-log-contents"
    rows="8"
    cols="30"
    id="eventLog"></textarea>
</div>

body {
  display: grid;
  grid-template-areas: "control log";
}

.controls {
  grid-area: control;
  display: flex;
  align-items: center;
  justify-content: center;
}

.event-log {
  grid-area: log;
}

.event-log-contents {
  resize: none;
}

label,
button {
  display: block;
}

#reload {
  height: 2rem;
}

JavaScript

const log = document.querySelector(".event-log-contents");
const reload = document.querySelector("#reload");

reload.addEventListener("click", () => {
  log.textContent = "";
  setTimeout(() => {
    window.location.reload(true);
  }, 200);
});

window.addEventListener("load", (event) => {
  log.textContent += "load\n";
});

document.addEventListener("readystatechange", (event) => {
  log.textContent += `readystate: ${document.readyState}\n`;
});

document.addEventListener("DOMContentLoaded", (event) => {
  log.textContent += "DOMContentLoaded\n";
});