--- title: load slug: Web/API/Window/load_event tags: - load translation_of: Web/API/Window/load_event original_slug: Web/Events/load ---

当整个页面及所有依赖资源如样式表和图片都已完成加载时，将触发load事件。

它与{{domxref("Document/DOMContentLoaded_event", "DOMContentLoaded")}}不同，后者只要页面DOM加载完成就触发，无需等待依赖资源的加载。

是否冒泡	否
能否取消	否
接口	{{domxref("Event")}}
Event handler property	{{domxref("GlobalEventHandlers/onload", "onload")}}

用法

当页面及资源完全加载后在控制台打印一段信息：

window.addEventListener('load', (event) => {
  console.log('page is fully loaded');
});

也可以使用onload实现：

window.onload = (event) => {
  console.log('page is fully loaded');
};

示例

HTML

<div class="controls">
  <button id="reload" type="button">Reload</button>
</div>

<div class="event-log">
  <label>Event log:</label>
  <textarea readonly class="event-log-contents" rows="8" cols="30"></textarea>
</div>

CSS

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;
}

JS

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

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

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

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

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

结果

规范

Specification	Status	Comment
{{SpecName('UI Events', '#event-type-load', 'load')}}	{{Spec2('UI Events')}}
{{SpecName('HTML WHATWG', '#delay-the-load-event', 'load event')}}	{{Spec2('HTML WHATWG')}}	此链接指向加载文档结束时执行步骤中的部分。“load”事件也会在许多元素上触发。请注意，规范中有很多地方涉及到可以"延迟加载事件"的内容。

浏览器兼容性

参阅

相关事件: {{domxref("Window/DOMContentLoaded_event", "DOMContentLoaded")}}, {{domxref("Document/readystatechange_event", "readystatechange")}}, {{domxref("Window/beforeunload_event", "beforeunload")}}, {{domxref("Window/unload_event", "unload")}}