JS 参考手册

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JavaScript

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HTML DOM

DOM Attributes DOM Document DOM Element DOM Events DOM Event 对象 DOM HTMLCollection DOM Location DOM Navigator DOM Screen DOM Style
alignContent alignItems alignSelf animation animationDelay animationDirection animationDuration animationFillMode animationIterationCount animationName animationTimingFunction animationPlayState background backgroundAttachment backgroundColor backgroundImage backgroundPosition backgroundRepeat backgroundClip backgroundOrigin backgroundSize backfaceVisibility border borderBottom borderBottomColor borderBottomLeftRadius borderBottomRightRadius borderBottomStyle borderBottomWidth borderCollapse borderColor borderImage borderImageOutset borderImageRepeat borderImageSlice borderImageSource borderImageWidth borderLeft borderLeftColor borderLeftStyle borderLeftWidth borderRadius borderRight borderRightColor borderRightStyle borderRightWidth borderSpacing borderStyle borderTop borderTopColor borderTopLeftRadius borderTopRightRadius borderTopStyle borderTopWidth borderWidth bottom boxShadow boxSizing captionSide caretColor clear clip color columnCount columnFill columnGap columnRule columnRuleColor columnRuleStyle columnRuleWidth columns columnSpan columnWidth counterIncrement counterReset cursor direction display emptyCells filter flex flexBasis flexDirection flexFlow flexGrow flexShrink flexWrap cssFloat font fontFamily fontSize fontStyle fontVariant fontWeight fontSizeAdjust height isolation justifyContent left letterSpacing lineHeight listStyle listStyleImage listStylePosition listStyleType margin marginBottom marginLeft marginRight marginTop maxHeight maxWidth minHeight minWidth objectFit objectPosition opacity order orphans outline outlineColor outlineOffset outlineStyle outlineWidth overflow overflowX overflowY padding paddingBottom paddingLeft paddingRight paddingTop pageBreakAfter pageBreakBefore pageBreakInside perspective perspectiveOrigin position quotes resize right scrollBehavior tableLayout tabSize textAlign textAlignLast textDecoration textDecorationColor textDecorationLine textDecorationStyle textIndent textOverflow textShadow textTransform top transform transformOrigin transformStyle transition transitionProperty transitionDuration transitionTimingFunction transitionDelay unicodeBidi userSelect verticalAlign visibility width wordBreak wordSpacing wordWrap widows zIndex
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Web APIs

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HTML 对象

<a> <abbr> <address> <area> <article> <aside> <audio> <b> <base> <bdo> <blockquote> <body> <br> <button> <canvas> <caption> <cite> <code> <col> <colgroup> <datalist> <dd> <del> <details> <dfn> <dialog> <div> <dl> <dt> <em> <embed> <fieldset> <figcaption> <figure> <footer> <form> <head> <header> <h1> - <h6> <hr> <html> <i> <iframe> <img> <ins> <input> button <input> checkbox <input> color <input> date <input> datetime <input> datetime-local <input> email <input> file <input> hidden <input> image <input> month <input> number <input> password <input> radio <input> range <input> reset <input> search <input> submit <input> text <input> time <input> url <input> week <kbd> <label> <legend> <li> <link> <map> <mark> <menu> <menuitem> <meta> <meter> <nav> <object> <ol> <optgroup> <option> <output> <p> <param> <pre> <progress> <q> <s> <samp> <script> <section> <select> <small> <source> <span> <strong> <style> <sub> <summary> <sup> <table> <tbody> <td> <tfoot> <th> <thead> <tr> <textarea> <time> <title> <track> <u> <ul> <var> <video>

其他参考手册

CSSStyleDeclaration JS 类型转换


onloadstart 事件

❮ DOM 事件 ❮ ProgressEvent

实例

在视频开始加载时执行 JavaScript:

<video onloadstart="myFunction()">
亲自试一试 »

页面下方有更多实例。


定义和用法

onloadstart 事件发生在浏览器开始寻找指定的音频/视频时。这就是加载过程开始的时候。

在音频/视频的加载过程中,会按以下顺序发生如下事件:

  1. onloadstart
  2. ondurationchange
  3. onloadedmetadata
  4. onloadeddata
  5. onprogress
  6. oncanplay
  7. oncanplaythrough

浏览器支持

表中的数字表示支持该事件的第一个浏览器版本。

事件
onloadstart Yes 9.0 Yes Yes Yes


语法

在 HTML 中:

<element onloadstart="myScript">
亲自试一试 »

在 JavaScript 中:

object.onloadstart = function(){myScript};
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在 JavaScript 中,使用 addEventListener() 方法:

object.addEventListener("loadstart", myScript);
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注释: Internet Explorer 8 或更早的版本不支持 addEventListener() 方法


技术细节

是否支持冒泡: No
是否支持取消: No
事件类型: ProgressEvent
支持的 HTML 标签: <audio> 和 <video>
DOM 版本: Level 3 Events

更多实例

实例

当音频开始加载时执行 JavaScript:

<audio onloadstart="myFunction()">
亲自试一试 »

❮ DOM 事件 ❮ ProgressEvent