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
DOM Window

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


JavaScript 字符串 substring() 方法

实例

从字符串中提取字符:

var str = "Hello world!";
var res = str.substring(1, 4);
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页面下方有更多实例。


定义和用法

substring() 方法从两个指定索引之间的字符串中提取字符,并返回新的子字符串。

此方法提取 "start" 和 "end" 之间字符串中的字符,不包括 "end" 本身。

如果 "start" 大于 "end",此方法将交换两个参数,这意味着 str.substring(1, 4) == str.substring(4, 1)。

如果 "start" 或 "end" 小于0,则将其视为0。

注释: substring() 方法不会更改原始字符串。


浏览器支持

方法
substring() Yes Yes Yes Yes Yes

语法

string.substring(start, end)

参数值

参数 描述
start 必需。开始提取的位置。第一个字符位于索引0处
end 可选。结束提取的位置(最多,但不包括)。如果省略,它将提取字符串的其余部分


技术细节

返回值: 包含提取字符的新字符串
JavaScript 版本: ECMAScript 1

更多实例

实例

从位置 2 开始提取,然后提取字符串的其余部分:

var str = "Hello world!";
var res = str.substring(2);
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实例

如果 "start" 大于 "end",它将交换两个参数:

var str = "Hello world!";
var res = str.substring(4, 1);
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实例

如果 "start" 小于 0,它将从索引位置 0 开始提取:

var str = "Hello world!";
var res = str.substring(-3);
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实例

只提取第一个字符:

var str = "Hello world!";
var res = str.substring(0, 1);
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实例

只提取最后一个字符:

var str = "Hello world!";
var res = str.substring(str.length - 1, str.length);
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