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JS 参考

按类别分类的 JS 按字母顺序排列的 JS

JavaScript

JS 数组
Array[ ] Array( ) at() concat() constructor copyWithin() entries() every() fill() filter() find() findIndex() findLast() findLastIndex() flat() flatMap() forEach() from() includes() indexOf() isArray() join() keys() lastIndexOf() length map() of() pop() prototype push() reduce() reduceRight() reverse() shift() slice() some() sort() splice() toReversed() toSorted() toSpliced() toString() unshift() values() valueOf() with()
JS 布尔值
constructor prototype toString() valueOf()
JS 类
constructor() extends static super
JS 日期
new Date() constructor getDate() getDay() getFullYear() getHours() getMilliseconds() getMinutes() getMonth() getSeconds() getTime() getTimezoneOffset() getUTCDate() getUTCDay() getUTCFullYear() getUTCHours() getUTCMilliseconds() getUTCMinutes() getUTCMonth() getUTCSeconds() now() parse() prototype setDate() setFullYear() setHours() setMilliseconds() setMinutes() setMonth() setSeconds() setTime() setUTCDate() setUTCFullYear() setUTCHours() setUTCMilliseconds() setUTCMinutes() setUTCMonth() setUTCSeconds() toDateString() toISOString() toJSON() toLocaleDateString() toLocaleTimeString() toLocaleString() toString() toTimeString() toUTCString() UTC() valueOf()
JS 错误
name message
JS 全局
decodeURI() decodeURIComponent() encodeURI() encodeURIComponent() escape() eval() Infinity isFinite() isNaN() NaN Number() parseFloat() parseInt() String() undefined unescape()
JS JSON
parse() stringify()
JS 地图
new Map clear() delete() entries() forEach() get() groupBy() has() keys() set() size values()
JS 数学
abs() acos() acosh() asin() asinh() atan() atan2() atanh() cbrt() ceil() clz32() cos() cosh() E exp() expm1() floor() fround() LN2 LN10 log() log10() log1p() log2() LOG2E LOG10E max() min() PI pow() random() round() sign() sin() sinh() sqrt() SQRT1_2 SQRT2 tan() tanh() trunc()
JS 数字
构造函数 EPSILON isFinite() isInteger() isNaN() isSafeInteger() MAX_SAFE_INTEGER MIN_SAFE_INTEGER MAX_VALUE MIN_VALUE NaN NEGATIVE_INFINITY POSITIVE_INFINITY parseFloat() parseInt() 原型 toExponential() toFixed() toLocaleString() toPrecision() toString() valueOf()
JS 对象
assign() 构造函数 create() defineProperties() defineProperty() entries() freeze() fromEntries() getOwnPropertyDescriptor() getOwnPropertyDescriptors() getOwnPropertyNames() groupBy() isExtensible() isFrozen() isSealed() keys() preventExtensions() 原型 seal() toString() valueOf() values()
JS 运算符 JS 优先级 JS Promise
all() allSettled() any() catch() finally() race() reject() resolve() then()
JS 正则表达式
修饰符: g i d m 分组: [abc] [^abc] [0-9] [^0-9] (x|y) 元字符: . \w \W \d \D \s \S \b \B \0 \n \f \r \t \v \xxx \xdd \uxxxx 量词: + * ? {X} {X,Y} {X,} $ ^ ?= ?! 属性: 构造函数 global ignoreCase lastIndex multiline source 方法: compile() exec() test() toString()
JS 集合
new Set add() clear() delete() entries() forEach() has() keys() size values()
JS 语句
break class const continue debugger do...while for for...in for...of function if...else let return switch throw try...catch var while
JS 字符串
at() charAt() charCodeAt() codePointAt() concat() 构造函数 endsWith() fromCharCode() includes() indexOf() lastIndexOf() length localeCompare() match() padEnd() padStart() 原型 repeat() replace() replaceAll() search() slice() split() startsWith() substr() substring() toLocaleLowerCase() toLocaleUpperCase() toLowerCase() toString() toUpperCase() trim() trimEnd() trimStart() valueOf()
JS TypedArray

Window

Window 对象
addeventlistener() alert() atob() blur() btoa() clearInterval() clearTimeout() close() closed confirm() console defaultStatus document focus() frameElement frames history getComputedStyle() innerHeight innerWidth length localStorage location matchMedia() moveBy() moveTo() name navigator open() opener outerHeight outerWidth pageXOffset pageYOffset parent print() prompt() removeEventlistener() resizeBy() resizeTo() screen screenLeft screenTop screenX screenY scrollBy() scrollTo() scrollX scrollY sessionStorage self setInterval() setTimeout() status stop() top
窗口控制台
assert() clear() count() error() group() groupCollapsed() groupEnd() info() log() table() time() timeEnd() trace() warn()
窗口历史记录
back() forward() go() length
窗口位置
assign() hash host hostname href origin pathname port protocol reload() replace() search
窗口导航器
appCodeName appName appVersion cookieEnabled geolocation javaEnabled() language onLine platform product taintEnabled() userAgent
窗口屏幕
availHeight availWidth colorDepth height pixelDepth width

HTML DOM

HTML 文档
activeElement addEventListener() adoptNode() anchors applets baseURI body charset characterSet close() cookie createAttribute() createComment() createDocumentFragment() createElement() createEvent() createTextNode() defaultView designMode doctype documentElement documentMode documentURI domain domConfig embeds execCommand() forms getElementById() getElementsByClassName() getElementsByName() getElementsByTagName() hasFocus() head images implementation importNode() inputEncoding lastModified links normalize() normalizeDocument() open() querySelector() querySelectorAll() readyState referrer removeEventListener() renameNode() scripts strictErrorChecking title URL write() writeln()
HTML 元素
accessKey addEventListener() appendChild() attributes blur() childElementCount childNodes children classList className click() clientHeight clientLeft clientTop clientWidth cloneNode() closest() compareDocumentPosition() contains() contentEditable dir firstChild firstElementChild focus() getAttribute() getAttributeNode() getBoundingClientRect() getElementsByClassName() getElementsByTagName() hasAttribute() hasAttributes() hasChildNodes() id innerHTML innerText insertAdjacentElement() insertAdjacentHTML() insertAdjacentText() insertBefore() isContentEditable isDefaultNamespace() isEqualNode() isSameNode() isSupported() lang lastChild lastElementChild matches() namespaceURI nextSibling nextElementSibling nodeName nodeType nodeValue normalize() offsetHeight offsetWidth offsetLeft offsetParent offsetTop outerHTML outerText ownerDocument parentNode parentElement previousSibling previousElementSibling querySelector() querySelectorAll() remove() removeAttribute() removeAttributeNode() removeChild() removeEventListener() replaceChild() scrollHeight scrollIntoView() scrollLeft scrollTop scrollWidth setAttribute() setAttributeNode() style tabIndex tagName textContent title
HTML 属性
getNamedItem() isId item() length name removeNamedItem() setNamedItem() specified value
HTML 集合
item() length namedItem()
HTML 节点列表
entries() forEach() item() keys() length values()
HTML DOMTokenList
add() contains() entries() forEach() item() keys() length remove() replace() supports() toggle() value values()
HTML 样式
alignContent alignItems alignSelf animation animationDelay animationDirection animationDuration animationFillMode animationIterationCount animationName animationTimingFunction animationPlayState background backgroundAttachment backgroundClip backgroundColor backgroundImage backgroundOrigin backgroundPosition backgroundRepeat 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 cssFloat cursor direction display emptyCells filter flex flexBasis flexDirection flexFlow flexGrow flexShrink flexWrap 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

HTML 事件

HTML 事件
中止 打印后 动画结束 动画迭代 动画开始 打印前 卸载前 失焦 可以播放 可以流畅播放 改变 点击 右键菜单 复制 剪切 双击 拖动 拖动结束 拖动进入 拖动离开 拖动经过 拖动开始 放下 持续时间改变 结束 错误 获取焦点 获得焦点 失去焦点 全屏改变 全屏错误 哈希改变 输入 无效 按键按下 按键按下 按键抬起 加载 数据加载完成 元数据加载完成 加载开始 消息 鼠标按下 鼠标进入 鼠标离开 鼠标移动 鼠标悬停 鼠标移出 鼠标抬起 离线 在线 打开 页面隐藏 页面显示 粘贴 暂停 播放 正在播放 进度 速度改变 大小改变 重置 滚动 搜索 已定位 正在定位 选择 显示 暂停 提交 暂停 时间更新 切换 触摸取消 触摸结束 触摸移动 触摸开始 过渡结束 卸载 音量改变 等待 滚动
HTML 事件对象
动画事件 剪贴板事件 拖动事件 事件 焦点事件 哈希改变事件 输入事件 键盘事件 鼠标事件 页面过渡事件 PopState 事件 进度事件 存储事件 触摸事件 过渡事件 Ui 事件 滚轮事件
HTML 事件属性
altKey (鼠标) altKey (键盘) 动画名称 冒泡 按钮 按钮 可取消 charCode clientX clientY code ctrlKey (鼠标) ctrlKey (键盘) currentTarget 数据 defaultPrevented deltaX deltaY deltaZ deltaMode 详情 已用时间 已用时间 事件阶段 inputType isTrusted key keyCode location metaKey (鼠标) metaKey (键盘) newURL oldURL offsetX offsetY pageX pageY persisted propertyName relatedTarget relatedTarget screenX screenY shiftKey (鼠标) shiftKey (键盘) 目标 targetTouches timeStamp touches 类型 which (鼠标) which (键盘) view
HTML 事件方法
getModifierState() preventDefault() stopImmidiatePropagation() stopPropagation()

Web APIs

API 画布 API 控制台 API 获取 API 全屏
exitFullscreen() fullscreenElement fullscreenEnabled() requestFullscreen()
API 地理位置
坐标 getCurrentPosition() 位置
API 历史记录 API 媒体查询列表 API 存储
clear() getItem() key() length removeItem() setItem()
API 验证 API Web
crypto.getRandomNumber()

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>

其他参考资料

CSSStyleDeclaration
cssText getPropertyPriority() getPropertyValue() item() length parentRule removeProperty() setProperty()
JS 转换


视频 poster 属性

❮ 视频对象

示例

更改视频的封面图片

document.getElementById("myVideo").poster = "/images/w3schoolscomlogo.png";
自己试试 »

描述

poster 属性设置或返回视频的 poster 属性的值。

poster 属性指定视频下载期间或用户点击播放按钮之前显示的图片。如果未包含此属性，将使用视频的第一帧。

浏览器支持

属性
poster 是 9.0 是 是 是

语法

返回 poster 属性

videoObject.poster

设置 poster 属性

videoObject.poster = URL

属性值

值 描述
URL 指定图片文件的 URL。

可能的取值

  • 绝对 URL - 指向另一个网站（例如 href="http://www.example.com/poster.jpg"）
  • 相对 URL - 指向网站内的文件（例如 href="poster.jpg"）

技术细节

返回值 一个字符串，表示封面图片的 URL。返回完整的 URL，包括协议（如 http://）

更多示例

示例

获取封面图片的 URL

var x = document.getElementById("myVideo").poster;
自己试试 »

相关页面

HTML 参考：HTML <video> poster 属性

❮ 视频对象
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