JS Reference

JS by Category JS by Alphabet

JavaScript

JS Array JS Boolean

constructor prototype toString() valueOf()

constructor() extends static super

JS Date JS Error

decodeURI() decodeURIComponent() encodeURI() encodeURIComponent() escape() eval() Infinity isFinite() isNaN() NaN Number() parseFloat() parseInt() String() undefined unescape()

parse() stringify()

JS Math JS Number

constructor isFinite() isInteger() isNaN() isSafeInteger() MAX_VALUE MIN_VALUE NEGATIVE_INFINITY NaN POSITIVE_INFINITY prototype toExponential() toFixed() toLocaleString() toPrecision() toString() valueOf()

JS Operators JS RegExp

Modifiers: g i m Groups: [abc] [^abc] [0-9] [^0-9] (x|y) Metacharacters: . \w \W \d \D \s \S \b \B \0 \n \f \r \t \v \xxx \xdd \uxxxx Quantifiers: + * ? {X} {X,Y} {X,} $ ^ ?= ?! Properties: constructor global ignoreCase lastIndex multiline source Methods: compile() exec() test() toString()

break class const continue debugger do...while for for...in for...of function if...else let return switch throw try...catch var while

Window

Window Object Window Console

assert() clear() count() error() group() groupCollapsed() groupEnd() info() log() table() time() timeEnd() trace() warn()

back() forward() go() length

Window Location

assign() hash host hostname href origin pathname port protocol reload() replace() search

Window Navigator

appCodeName appName appVersion cookieEnabled geolocation javaEnabled() language onLine platform product taintEnabled() userAgent

availHeight availWidth colorDepth height pixelDepth width

HTML DOM

DOM Document DOM Element

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

getNamedItem() isId item() length name removeNamedItem() setNamedItem() specified value

abort afterprint animationend animationiteration animationstart beforeprint beforeunload blur canplay canplaythrough change click contextmenu copy cut dblclick drag dragend dragenter dragleave dragover dragstart drop durationchange ended error focus focusin focusout fullscreenchange fullscreenerror hashchange input invalid keydown keypress keyup load loadeddata loadedmetadata loadstart message mousedown mouseenter mouseleave mousemove mouseover mouseout mouseup offline online open pagehide pageshow paste pause play playing progress ratechange resize reset scroll search seeked seeking select show stalled submit suspend timeupdate toggle touchcancel touchend touchmove touchstart transitionend unload volumechange waiting wheel altKey altKey animationName bubbles button buttons cancelable charCode clientX clientY code ctrlKey ctrlKey currentTarget data defaultPrevented deltaX deltaY deltaZ deltaMode detail elapsedTime elapsedTime eventPhase getModifierState() inputType isTrusted key keyCode location metaKey metaKey newURL oldURL pageX pageY persisted preventDefault() propertyName relatedTarget relatedTarget screenX screenY shiftKey shiftKey stopImmediatePropagation() stopPropagation() target targetTouches timeStamp touches type which which view

DOM Event Objects

AnimationEvent ClipboardEvent DragEvent Event FocusEvent HashChangeEvent InputEvent KeyboardEvent MouseEvent PageTransitionEvent PopStateEvent ProgressEvent StorageEvent TouchEvent TransitionEvent UiEvent WheelEvent

DOM HTMLCollection

item() length namedItem()

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

Web APIs

API Console API Fullscreen

exitFullscreen() fullscreenElement fullscreenEnabled() requestFullscreen()

API Geolocation

coordinates position

API History API MediaQueryList API Storage

key() length getItem() setItem() removeItem() clear()

HTML Objects

<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>

Other References

CSSStyleDeclaration

cssText getPropertyPriority() getPropertyValue() item() length parentRule removeProperty() setProperty()

ビデオプリロードプロパティ

❮ビデオオブジェクト

例

ページの読み込み時に動画を読み込む必要があると作成者が考えているかどうか、またどのように考えているかを確認します。

var x = document.getElementById("myVideo").preload;

定義と使用法

preloadプロパティは、ビデオのpreload属性の値を設定または返します。

preload属性は、ページの読み込み時にビデオを読み込む必要があるかどうか、およびその方法を作成者が考えるかどうかを指定します。

preload属性を使用すると、作成者は、最高のユーザーエクスペリエンスにつながると考えていることについて、ブラウザーにヒントを提供できます。この属性は、場合によっては無視されることがあります。

注： autoplay属性が存在する場合、preload属性は無視されます。

ブラウザのサポート

Property
preload	Yes	9.0	Yes	Yes	Yes

構文

プリロードプロパティを返します。

videoObject.preload

プリロードプロパティを設定します。

videoObject.preload = "auto|metadata|none"

プロパティ値

Value	Description
auto	The author thinks that the browser should load the entire video when the page loads
metadata	The author thinks that the browser should load only metadata when the page loads
none	The author thinks that the browser should NOT load the video when the page loads

技術的な詳細

戻り値：	プリロードする必要のあるデータ（存在する場合）を表す文字列。可能な戻り値は、「auto」、「metadata」、または「none」です。値の意味については、「プロパティ値」を参照してください。

その他の例

例

さまざまなプロパティ値を設定する方法のデモンストレーション：

document.getElementById("myVideo").preload = "none";
document.getElementById("myVideo").preload = "auto";

関連ページ

HTMLリファレンス：HTML <video>プリロード属性

❮ビデオオブジェクト