Iframe onload mdn. In particular, it will be hard to adjust the window size so as to see a difference in the reported height. One crucial aspect of Jul 17, 2025 · The download() function of the downloads API downloads a file, given its URL and other optional preferences. When the IFrame has loaded, we register an onmessage handler for MessageChannel. Apr 3, 2025 · Web Workers makes it possible to run a script operation in a background thread separate from the main execution thread of a web application. Is this even possible? May 22, 2025 · The same-origin policy is a critical security mechanism that restricts how a document or script loaded by one origin can interact with a resource from another origin. Note: The load event on HTMLBodyElement is actually an alias for the window. Apr 7, 2023 · If the iframe and the iframe's parent document are Same Origin, returns a Document (that is, the active document in the inline frame's nested browsing context), else returns null. Apr 10, 2025 · The loading property of the HTMLIFrameElement interface is a string that provides a hint to the user agent indicating whether the iframe should be loaded immediately on page load, or only when it is needed. <iframe> は HTML の要素で、入れ子になった閲覧コンテキストを表現し、現在の HTML ページに他のページを埋め込むことができます。 Mar 11, 2021 · 学习JavaScript资源加载技巧：掌握onload和onerror事件处理，实现脚本、图片等外部资源的动态加载与错误监控。了解跨域访问策略，优化网页性能与用户体验。 JavaScriptのIFrameオブジェクトについて、DOM操作やプロパティに関する詳細な解説を提供します。 Sep 11, 2025 · In an HTML document, the document. It is fired after: beforeunload (cancellable event But keeping your Iframe idea, You could also load your HTML inside your iframe tag and set it as the srcdoc value. Sep 11, 2025 · The load event is fired when the whole page has loaded, including all dependent resources such as stylesheets, scripts (including async, deferred, and module scripts), iframes, and images, except those that are loaded lazily. Say you wanted to include the MDN glossary on one of your web pages using the <iframe> element, you might try something like the next code example. 0 indicates that navigation happens in the tab's top-level browsing context, not in a nested <iframe>. onload (img is the last resource) and window. But the thing with these editors is that you have to find a way to keep the focus and the selection when the user is clicking on all the buttons across the interface. May 23, 2011 · I've been playing around with adding hidden iframe elements to a page, and I want to manipulate the DOM of the these once loaded. Sep 23, 2024 · Lazy-loading of <iframe> elements defers offscreen iframes from being loaded until the user scrolls near them. Sep 11, 2025 · Using the File API, web content can ask the user to select local files and then read the contents of those files. IFrame Object The IFrame object represents an HTML <iframe> element. var channel = new MessageChannel(); Document. , between a page and a pop-up that it spawned, or between a page and an iframe embedded within it. var iframe_jquery = $("<iframe>") . Apr 10, 2025 · Lazy loading is a strategy to identify resources as non-blocking (non-critical) and load these only when needed. These are windows to load other web pages on our website and interact with them. This article explains why this is an important 5 days ago · The Window interface represents a window containing a DOM document; the document property points to the DOM document loaded in that window. Jun 23, 2025 · HTML <script> elements expose the HTMLScriptElement interface, which provides special properties and methods for manipulating the behavior and execution of <script> elements (beyond the inherited HTMLElement interface). requestFullscreen() method issues an asynchronous request to make the element be displayed in fullscreen mode. Jan 23, 2017 · The load event is fired when a resource and its dependent resources have finished loading. May 19, 2025 · This article demonstrates how to use the Fullscreen API to place a given element into fullscreen mode, as well as how to detect when the browser enters or exits fullscreen mode. Sep 11, 2025 · The JavaScript exception "Permission denied to access property" occurs when there was an attempt to access an object for which you have no permission. I've noticed that I can't start manipulating the DOM immediately af Sep 11, 2025 · Learn about the DOMContentLoaded event, its type, syntax, code examples, specifications, and browser compatibility on MDN Web Docs. I have no control over test. For example, if a script has an execution error or an image can't be found or May 2, 2025 · Note: The example output here is in an <iframe>, so the reported width and height values are for the <iframe>, not the window that this page is in. This attribute is read-only, but its properties can be manipulated like the global Window object. This selection can be done by either using an HTML <input type="file"> element or by drag and drop. 5 days ago · The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget. Mar 6, 2024 · The MessagePort interface of the Channel Messaging API represents one of the two ports of a MessageChannel, allowing messages to be sent from one port and listening out for them arriving at the other. 5 days ago · The open() method of the Window interface loads a specified resource into a new or existing browsing context (that is, a tab, a window, or an iframe) under a specified name. Frame/IFrame onload 事件 Frame/IFrame 对象 定义和用法 onload 事件在frame或者iframe载入完成后被触发。 语法 onload='JavaScriptCode' 参数 描述 JavaScriptCode 必须。在事件触发后执行的Javascript代码。 浏览器支持 所有主要浏览器都支持 onload 事件 实例 实. readyState becomes complete when all resources (iframe and img) are loaded. The contentWindow property returns the Window object generated by an iframe element (through the window object, you can access the document object and then any one of the document's elements). addEventListener() from the target. contentWindow 属性返回 HTMLIFrameElement 的 Window 对象。将消息源映射到 iframe 此示例可在包含多个 iframe 的页面中运行，其中任何一个都可以使用 Window. This article introduces custom elements, and walks through some examples. See "Cross-origin script API access Oct 5, 2020 · For <iframe>, the iframe. sendMouseEvent() Sends a MouseEvent to the <iframe> 's content. Jan 24, 2020 · The other situation when iframes saved my life was when I had to build a WYSIWYG editor for a customer. If you are not using jQuery, just put an id into the div and replace this part of code: Mar 13, 2025 · The Clipboard API provides the ability to respond to clipboard commands (cut, copy, and paste), as well as to asynchronously read from and write to the system clipboard. This is in contrast to DOMContentLoaded, which is fired as soon as the page DOM has been loaded, without waiting for resources to finish loading. The print media type sets the styles for printed media; these styles will only be used for printed content. Switching to complete state means the same as window. Feb 22, 2017 · There was attempt to access an object for which you have no permission. Feb 12, 2012 · I am using AngularJS inside the iFrame, and using ng-include, which delays the loading of the included files. readyState property describes the loading state of the document. Aug 20, 2025 · The setTimeout() method of the Window interface sets a timer which executes a function or specified piece of code once the timer expires. This saves data, speeds up the loading of other parts of the page, and reduces memory usage. Note that specificity and Jun 23, 2025 · The beforeunload event is fired when the current window, contained document, and associated resources are about to be unloaded. onbeforeunload event handler property contains the code executed when the beforeunload is sent. Related Evidence and Reference Links For further exploration, here are some additional resources that provide more information on capturing the load complete event of an iframe: MDN Web Docs – HTMLIFrameElement W3Schools – The onload Event Stack Overflow – How can I make an iframe load as soon as possible? Summary Aug 22, 2025 · Even the live editable examples you've been using through this course are implemented using <iframe> s. onload always works after all other load handlers. Oct 30, 2023 · This in-depth guide explains how to effectively implement iframe onload events using JavaScript for enhanced webpage functionality. Jun 23, 2025 · Note: The load event on HTMLBodyElement is actually an alias for the window. Feb 2, 2024 · Execute a JavaScript Function on a Load of an iFrame Implement on load Event in iframe Using Pure JavaScript Implement on load Event in iframe Using onload Event Listner Use Inline Function in HTML’s onload Event Handler of iframe <iframe> stands for The Inline Frame Element. createElement() method creates the HTML element specified by localName, or an HTMLUnknownElement if localName isn't recognized. May 2, 2025 · The readystatechange event is fired when the readyState attribute of a document has changed. postMessage() 发送信息。当页面接收到消息时，就会知道哪个 iframe 包含发送消息的窗口。 为了做到这一点，当接收到消息时，页面首先检查消息是否来自 Jun 23, 2025 · The error event is fired on an element when a resource failed to load, or can't be used. port1 and transfer MessageChannel. onload イベントの別名です。 従って、 load イベントは <body> 要素においては、その文書のすべてのリソースが読み込まれたかエラーになったときに、一度だけ発生します。 Sep 25, 2023 · Value A Window object. When a message is received back from the IFrame, the onMessage function outputs the message to a Nov 26, 2023 · The href property of the Location interface is a stringifier that returns a string containing the whole URL, and allows the href to be updated. The worker thread can perform tasks without interfering with the user interface. 5 days ago · DOM events Events are fired to notify code of "interesting changes" that may affect code execution. Description Access to the Window returned by contentWindow is subject to the rules defined by the same-origin policy, meaning that if the iframe is same-origin with the parent, then the parent can access the iframe's document and its internal DOM, and if they are cross-origin, it gets very limited access to the window's attributes. The document is still visible and the event is still cancelable. Jun 23, 2025 · The Fullscreen API adds methods to present a specific Element (and its descendants) in fullscreen mode, and to exit fullscreen mode once it is no longer needed. This makes it possible to present desired content—such as an online game—using the user's entire screen, removing all browser user interface elements and other applications from the screen until fullscreen mode is shut off. Nov 16, 2024 · 3 body tag of html has onload function. It may contain one or more audio sources, represented using the src attribute or the <source> element: the browser will choose the most suitable one. ) 对于终端用户所有资源均不可见 界面交互无效 (window. open, alert, confirm 等. Mar 22, 2019 · There are five ways to check if a page has loaded in vanilla JavaScript. Summary. The focused element is the element that will receive keyboard and similar events by default. png is 100mb for some reason. Jul 9, 2025 · The <iframe> HTML element represents a nested browsing context, embedding another HTML page into the current one. The onload attribute can be used to check the visitor's browser type and browser version, and load the proper version of the web page based on the information. readyState 属性描述了 document 的加载状态。 当该属性值发生变化时，会在 document 对象上触发 readystatechange 事件。 In the following example, you can see a new channel being created using the MessageChannel() constructor. You should not have to mind about quotes nor turning it into a dataUri but only mind to fire onload once. Jul 4, 2025 · The HTTP Content-Security-Policy (CSP) frame-src directive specifies valid sources for nested browsing contexts loading using elements such as <frame> and <iframe>. appendTo(container); // container is a jQuery load イベントは、ページ全体が、スタイルシートや画像などのすべての依存するリソースを含めて読み込まれたときに発生します。 これは DOMContentLoaded が、ページの DOM の読み込みが完了すれば、リソースの読み込みが完了するのを待たずに発生するのと対照的です。 注意： HTMLBodyElement 上的 load 事件实际上是 window. A positive value indicates that navigation happens in a nested iframe. In this Sep 23, 2024 · Purpose: The onload event is fired when a specific resource (image, script, iframe, etc. Note: The . One of the common tasks developers face is triggering specific functions once an iframe has loaded. ). live() and . May 5, 2017 · 关于 postMessage 的详细介绍请戳这里，不过MDN的文档太详细了，导致有些同学看完还是一脸懵逼，下面我们就来看看怎么用 postMessage 实现iframe跨域通信，当你会用了之后再回去看文档，感觉是完全不同的。 Aug 12, 2025 · The Element. Jul 9, 2025 · The autofocus global attribute is a Boolean attribute indicating that an element should be focused on page load, or when the <dialog> that it is part of is displayed. HTMLIFrameElement. When the value of this property changes, a readystatechange event fires on the document object. loading 是 HTMLIFrameElement 接口的一个字符串属性，它为 用户代理 提供了一个提示，指示 iframe 应该在页面加载时立即加载，还是仅在需要时加载。 这可以用于优化文档内容的加载。页面加载时可见的 iframe 可以立即下载（预加载），而初始页面加载时可能位于屏幕外的 iframe 可以延迟下载——就在它们 HTMLIFrameElement 接口的 loading 属性为 用户代理 提供一个提示字符串，表示是否应在页面加载时立即加载 iframe，或者仅在需要时才加载。 这可用于优化文档内容的加载。在页面加载时可见的 iframe 可以立即（即时）下载，而可能在初始页面加载时位于屏幕外的 iframe 可以懒加载——它们仅在将要出现在 Jul 21, 2025 · Frame in which the navigation is occurring. onload 事件，无论是成功加载还是出现 error。 这是出于历史原因。 跨源策略 这里有一条规则：来自一个网站的脚本无法访问其他网站的内容。 例如，位于 https://facebook. This name attribute can be used to reference the element in a JavaScript, or as the value of the target attribute of an <a> or <form> element, or the formtarget attribute of an <input> or <button> element. onload 事件的别名。 因此， load 事件仅在文档的所有资源加载或出错后才会在 <body> 元素上触发。 Jul 26, 2024 · The Channel Messaging API allows two separate scripts running in different browsing contexts attached to the same document (e. 5 days ago · The window. May 2, 2025 · The popstate event of the Window interface is fired when the active history entry changes while the user navigates the session history. onload is most often used within the element to execute a script once a web page has completely loaded all content (including images, script files, CSS files, etc. Jan 20, 2019 · firefox cannot support iframe_onload? 1 reply 1 has this problem 4 views Last reply by jscher2000 - Support Volunteer 6 years ago DOMContentLoaded 事件在 HTML 文档完全解析且所有延迟脚本下载和执行完毕后触发，不会等待其他内容加载完成。 Mar 23, 2018 · From MDN: The WindowEventHandlers. requestIdleCallback() method queues a function to be called during a browser's idle periods. getActive() Indicates whether the current browser <iframe> is the currently active frame. This enables developers to perform background and low priority work on the main thread, without impacting latency-critical events such as animation and input response. May 2, 2025 · The loadeddata event is fired when the frame at the current playback position of the media has finished loading; often the first frame. onload event. Nov 11, 2024 · Additional Resources MDN - Using the <iframe> element MDN - The load event Cross-Origin Resource Sharing (CORS) - MDN By following this guide, you'll have a solid framework for implementing loading state detection in iframes that enhances user interaction with your web applications. When a message is received back from the IFrame, the onMessage function simply outputs the message to a paragraph. Copy Summary View Open Bug 929899 Opened 12 years agoUpdated 3 years ago iframe onload does not fire when the tcp connection reset by server Jun 23, 2025 · The window. . onload. postMessage() method safely enables cross-origin communication between Window objects; e. target isn't set by Firefox, IE9 or Chrome, which is required to do event delegation. In order to get the content from the page referred to by the iframe's src attribute, you need to access the iframe's contentDocument property. , two <iframe> elements, the main document and a single <iframe>, or two documents via a SharedWorker) to communicate directly, passing messages between each other through two-way channels (or pipes) with a port at each end. Happy coding! May 2, 2025 · The unload event is fired when the document or a child resource is being unloaded. Sep 14, 2010 · One technique is to set a JavaScript timeout when you make the request. I tried to apply this on an iframe but it does not seems to work. onload = function () {}. Dec 26, 2024 · Seamless Communication Between Parent and iFrame Using postMessage () In the world of web development, embedding iframes is a common practice to integrate third-party content or isolate Sep 12, 2025 · Using custom elements One of the key features of web components is the ability to create custom elements: that is, HTML elements whose behavior is defined by the web developer, that extend the set of elements available in the browser. com's slow image. The onload event occurs when an object has been loaded. pushState() has been used to add a history entry to the history stack, that history entry is used instead. onload event triggers when the iframe loading finished, both for successful load and in case of an error. port2 to the IFrame using the window. I was trying to print the contents of the Iframe upon the onload event, but it was firing too soon. Access an IFrame Object You can access an <iframe> element by using getElementById (): Sep 1, 2025 · The preload value of the <link> element's rel attribute specifies resources to load early in the page lifecycle, improving performance. If your timeout fires before the iframe onload event, the content didn't load. In addition, they can make network requests using the fetch() or XMLHttpRequest APIs. ) has finished loading successfully. com 的用户 Aug 28, 2024 · Triggering Functions After Iframe Loads: A Simple Guide If you've ever worked with iframes in web development, you know that managing them can be a bit tricky. Sep 9, 2025 · The Document. The load event does not correctly bubble up the parent document and the event. The sites or webpages loaded using The onload event occurs when an object has been loaded, commonly used to execute a script after the page or image is fully loaded. postMessage method along with a message. In this blog post, we'll Apr 18, 2017 · The contentWindow property returns the Window object of an iframe element. 5 days ago · Autoplay guide for media and Web Audio APIs Automatically starting the playback of audio (or videos with audio tracks) immediately upon page load can be an unwelcome surprise to users. html, but I must include the iframe in my page. Before diving into using <iframe> elements, there are some security concerns to be aware of. The <iframe> gains support for the methods of the EventTarget interface addEventListener(), removeEventListener(), and dispatchEvent(). May 2, 2025 · The abort event is fired when the resource was not fully loaded, but not as the result of an error. Sep 2, 2024 · The srcdoc property of the HTMLIFrameElement specifies the content of the page. Jul 9, 2025 · The popover global attribute is used to designate an element as a popover element. Jun 6, 2024 · Explore the best features of the iframe tag, learn how to use them effectively, and secure them against vulnerabilities with this comprehensive guide. The unload event is fired when the document or a child resource is being unloaded. This can be crucial for ensuring that your web application operates smoothly without errors or race conditions. Here we can see that it happens in about the same time as img. HTML 元素 <iframe> 表示嵌套的浏览上下文。它能够将另一个 HTML 页面嵌入到当前页面中。 メモ: 実際には load イベントは、 HTMLBodyElement においては、 window. Jun 23, 2025 · The HTMLElement. But instead of this declarative approach, web apps sometimes use JavaScript APIs such as fetch() to send data programmatically to an endpoint that expects a form submission. May 7, 2025 · The loadstart event is fired when the browser has started to load a resource. delegate() methods cannot be used to detect the load event of an iframe. The <script> element can also be used with other languages, such as WebGL's GLSL shader programming language and JSON. You could then set iframe. Therefore, the load event will only fire on the <body> element once all of the document's resources have loaded or errored. focus() method sets focus on the specified element, if it can be focused. 动态创建的 display 为 none 的 iframe 元素， onload 事件 不会执行 ！ 昨天业务需求中碰到一个关于 iframe 不能正常跳转的棘手问题，一直猜测是 onload 事件引起的，虽然最后用 promise 暂时解决了，但是考虑到一些老版本的浏览器还需要 polyfill 去兼容一下，不必要的引入了 js 增加开销，所以今天研究了一 5 days ago · The Promise object represents the eventual completion (or failure) of an asynchronous operation and its resulting value. Jul 3, 2025 · The navigate event of the Navigation interface is fired when any type of navigation is initiated, allowing you to intercept as required. As with lazy-loading for images, use the loading attribute to tell the browser you want to lazy-load an iframe. addClass("foo") . HTMLIFrameElement The innerHTML of your iframe is blank because your iframe tag doesn't surround any content in the parent document. Sep 23, 2009 · Weirdly enough I can get this to work as <iframe onload=""> but not with iframe. huge. View Open Bug 444165 Opened 16 years agoUpdated 2 years ago iframe onload event does not fire if the src URL is invalid Sep 11, 2025 · Web Workers are a simple means for web content to run scripts in background threads. May 2, 2025 · The pageshow event is sent to a Window when the browser displays the window's document due to navigation. Definition and Usage The name attribute specifies a name for an iframe. load 事件在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触发。它与 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。 5 days ago · The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target. The load event is fired when the page has loaded, including resources such as stylesheets and images. com 的脚本无法读取位于 https://gmail. src to about:blank, delete, or reuse the iframe. Oct 12, 2023 · iframe コンテンツが読み込まれたら、JavaScript でメソッドを実行する方法を見てみましょう。 iFrame のロード時に JavaScript 関数を実行する iframe HTML タグの onload イベントハンドラーを使用できます。 iframe のすべての要素が読み込まれると、イベントが発生し loading は HTMLIFrameElement インターフェイスのプロパティで、ユーザーエージェントに iframe をページ読み込み時に即座に読み込むか、必要な時にのみ読み込むかを指定するヒントを提供する文字列です。 The <script> HTML element is used to embed executable code or data; this is typically used to embed or refer to JavaScript code. The document is still visible and the event is still cancelable at this point. Frame/IFrame 的 onload 事件是在加载完成后执行操作的重要方式，通过它我们可以方便地处理加载完成后的逻辑。 在实际开发中，我们可以根据具体需求在 onload 事件中执行不同的操作，为用户提供更好的体验。 1 day ago · The <audio> HTML element is used to embed sound content in documents. Oct 3, 2024 · When the IFrame has loaded, we register an onmessage handler for MessageChannel. Checking for readyState === "complete" did the trick, since it doesn't change until everything is loaded. The onload attribute can also be used to deal with cookies (see "More Examples" below). That’s for historical reasons. Is there a way to load the iframe without blocking my page's onload event OR waiting until my page's onload event to set the iframe's src attribute I want #1 because I don't want JS on my page to have to wait for example. Add this at the end of your stylesheet. It can also be the destination for streamed media, using a MediaStream. This includes any dependent resources it might have. It changes the current history entry to that of the last page the user visited or, if history. You can use this Window object to access the iframe's document and its internal DOM. Code examples that accompany various MDN DOM and Web API documentation pages - mdn/dom-examples Aug 18, 2025 · A cross-site scripting (XSS) attack is one in which an attacker is able to get a target site to execute malicious code as though it was part of the website. This event fires when a window is about to unload its resources. It's a way to shorten the length of the critical rendering path, which translates into reduced page load times. The advantage of this is that laborious processing can be performed in a separate thread, allowing the main (usually the UI) thread to run without being blocked/slowed down. This is likely an iframe element loaded from a different domain for which you violated the same-origin policy. The HTML Inline Frame element (<iframe>) represents a nested browsing context, embedding another HTML page into the current one. Apr 10, 2025 · The HTMLIFrameElement interface provides special properties and methods (beyond those of the HTMLElement interface it also has available to it by inheritance) for manipulating the layout and presentation of inline frame elements. g. Jul 14, 2025 · Using media queries and @page to control printed content You can use the CSS @media at-rule to set different styles for your webpage when it is printed on paper or as a PDF versus when it is displayed on the screen. Using the onload event you can remove the loading image after the source page is loaded inside your iframe. Jun 7, 2024 · Opens the print dialog to print the current document. Description The onloadeddata event occurs when a media frame is loaded, but does not guarantee that enough data is available to begin playing. Functions are generally called in first-in-first-out order; however, callbacks which have a timeout specified may be called May 1, 2017 · Returns the element (such as iframe or object) in which the window is embedded, or null if the element is either top-level or is embedded into a document with a different script origin; that is, in cross-origin situations. The event listener to be removed is identified using a combination of the event type, the event listener function itself, and various optional options that may affect the matching process; see Matching event listeners for removal. Aug 26, 2025 · The load event is fired when an XMLHttpRequest transaction completes successfully. Once created, a worker can send messages to the JavaScript code that created it by posting messages to an event handler specified by that code Jun 23, 2025 · The pushState() method of the History interface adds an entry to the browser's session history stack. The onloadeddata event occurs after onloadedmetadata and before oncanplay. Dec 24, 2016 · I use the following code to dynamically create an iframe. These can arise from user interactions such as using a mouse or resizing a window, changes in the state of the underlying environment (e. sendTouchEvent() Sends a TouchEvent to the <iframe> 's content. Jul 9, 2025 · The <iframe> HTML element represents a nested browsing context, embedding another HTML page into the current one. Because an iframe offers an isolated environment, this means that the focus or the selection is never lost when you are In the dynamic world of web development, mastering JavaScript is a pivotal step for enhancing website functionality and user interaction. In order to give users control over this, browsers often provide various forms of autoplay blocking. Audio-related methods The following methods allow direct control of sound in the browser element. Jun 5, 2017 · Sets the current <iframe> as the active frame, which has an effect on how it is prioritized by the process manager. The difference is that window. Oct 14, 2022 · document. While autoplay of media serves a useful purpose, it should be used carefully and only when needed. Oct 4, 2018 · The following snippet will replace the PNG image with GIF image if the link is broken or does not exist. ) 错误不会停止卸载文档的过程 请注意 unload 事件也遵循文档树：父 iframe 会在子 iframe 卸载前卸载 Apr 11, 2025 · Sending forms through JavaScript When a user submits an HTML form, for example by clicking the submit button, the browser makes an HTTP request to send the data in the form. load 事件在整个页面加载完成后触发，包括所有依赖资源，例如样式表、脚本、iframe 和图像，但那些 延迟加载 的资源除外。这与 DOMContentLoaded 形成对比，后者在页面 DOM 加载完成后立即触发，而无需等待资源加载完成。 此事件不可取消，也不冒泡。 Mar 6, 2024 · The MessageChannel interface of the Channel Messaging API allows us to create a new message channel and send data through it via its two MessagePort properties. 它在下面两个事件后被触发： beforeunload (可取消默认行为的事件) pagehide 文档处于以下状态： 所有资源仍存在 (图片，iframe 等. Each event is represented by an object that is based on the Event interface, and Nov 13, 2020 · 对于 <iframe> 来说，iframe 加载完成时会触发 iframe. , low battery or media events from the operating system), and other causes. Jun 23, 2025 · The error event is fired on a Window object when a resource failed to load or couldn't be used — for example if a script has an execution error. iys wchmnn zjfrbl iqahp xodamr ywdt ylwrh avxi stpkgq rrev