JS 参考手册

JS 参考手册(类别排序) JS 参考手册(字母排序)

JavaScript

JS Array JS Boolean JS Classes JS Date JS Error JS Global JS JSON JS Math JS Number JS 运算符 JS RegExp JS 语句 JS String

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

API Console API Geolocation API History API Storage

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


HTML DOM scrollTop 属性

❮ Element 对象

实例

获取 <div> 元素的内容水平和垂直滚动的像素数:

var elmnt = document.getElementById("myDIV");
var x = elmnt.scrollLeft;
var y = elmnt.scrollTop;
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页面下方有更多实例。


定义和用法

scrollTop 属性设置或返回元素内容垂直滚动的像素数。

提示: 使用 scrollLeft 属性设置或返回元素内容水平滚动的像素数。

提示: 要向元素添加滚动条,请使用 overflow 属性。

提示: 在滚动元素的滚动条时发生 onscroll 事件。


浏览器支持

属性
scrollTop Yes Yes Yes Yes Yes

语法

返回 scrollTop 属性:

element.scrollTop

设置 scrollTop 属性:

element.scrollTop = pixels

属性值

描述
pixels 指定垂直滚动元素内容的像素数。

特别说明:
  • 如果该数字为负值,则该数字设置为 "0"
  • 如果无法滚动该元素,则将数字设置为 "0"
  • 如果该数字大于允许的最大滚动量,则该数字将设置为最大数字


技术细节

返回值: 一个数字, 表示元素内容垂直滚动的像素数

更多实例

实例

将 <div> 元素的内容水平滚动至50像素,垂直滚动至10像素:

var elmnt = document.getElementById("myDIV");
elmnt.scrollLeft = 50;
elmnt.scrollTop = 10;
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实例

将 <div> 元素的内容水平滚动50像素,垂直滚动10像素:

var elmnt = document.getElementById("myDIV");
elmnt.scrollLeft += 50;
elmnt.scrollTop += 10;
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实例

将 <body> 的内容水平滚动30像素,垂直滚动10像素:

var body = document.body; // Safari
var html = document.documentElement; // Chrome, Firefox, IE and Opera places the overflow at the <html> level, unless else is specified. Therefore, we use the documentElement property for these browsers
body.scrollLeft += 30;
body.scrollTop += 10;
html.scrollLeft += 30;
html.scrollTop += 10;
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实例

在不同滚动位置的类名之间切换——当用户从页面顶部向下滚动50个像素时,类名"test"将被添加到元素中(再次向上滚动时会被删除)。

window.onscroll = function() {myFunction()};

function myFunction() {
  if (document.body.scrollTop > 50 || document.documentElement.scrollTop > 50) {
    document.getElementById("myP").className = "test";
  } else {
    document.getElementById("myP").className = "";
  }
}
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实例

当用户从页面顶部向下滚动350像素时,在元素中滑动(添加 slideUp 类):

window.onscroll = function() {myFunction()};

function myFunction() {
  if (document.body.scrollTop > 350 || document.documentElement.scrollTop > 350) {
    document.getElementById("myImg").className = "slideUp";
  }
}
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实例

Draw a triangle on scroll:

<!-- Use SVG to draw the triangle (has to be <path>) -->
<svg id="mySVG">
  <path fill="none" stroke="red" stroke-width="3" id="triangle" d="M150 0 L75 200 L225 200 Z">
</svg>

<script>
// Get the id of the <path> element and the length of <path>
var triangle = document.getElementById("triangle");
var length = triangle.getTotalLength();

// The start position of the drawing
triangle.style.strokeDasharray = length;

// Hide the triangle by offsetting dash. Remove this line to show the triangle before scroll draw
triangle.style.strokeDashoffset = length;

// Find scroll percentage on scroll (using cross-browser properties), and offset dash same amount as percentage scrolled
window.addEventListener("scroll", myFunction);

function myFunction() {
  var scrollpercent = (document.body.scrollTop + document.documentElement.scrollTop) / (document.documentElement.scrollHeight - document.documentElement.clientHeight);

  var draw = length * scrollpercent;

  // Reverse the drawing (when scrolling upwards)
  triangle.style.strokeDashoffset = length - draw;
}
</script>
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❮ Element 对象