我有这个输入元素:
<input type="text" class="textfield" value="" id="subject" name="subject">
然后我还有一些其他元素,比如其他标签的&<textarea>标签等等。。。
当用户点击<input id=“#subject”>时,页面应该滚动到页面的最后一个元素,并且应该使用一个漂亮的动画(应该滚动到底部而不是顶部)。
页面的最后一项是带有#submit的提交按钮:
<input type="submit" class="submit" id="submit" name="submit" value="Ok, Done.">
动画不应该太快,应该是流畅的。
我正在运行最新的jQuery版本。我宁愿不安装任何插件,而是使用默认的jQuery特性来实现这一点。
我设置了一个模块滚动元素npm安装滚动元素。它的工作原理如下:
import { scrollToElement, scrollWindowToElement } from 'scroll-element'
/* scroll the window to your target element, duration and offset optional */
let targetElement = document.getElementById('my-item')
scrollWindowToElement(targetElement)
/* scroll the overflow container element to your target element, duration and offset optional */
let containerElement = document.getElementById('my-container')
let targetElement = document.getElementById('my-item')
scrollToElement(containerElement, targetElement)
在以下SO帖子的帮助下编写:
没有jquery的元素的顶部偏移量不带jquery的滚动条动画
代码如下:
export const scrollToElement = function(containerElement, targetElement, duration, offset) {
if (duration == null) { duration = 1000 }
if (offset == null) { offset = 0 }
let targetOffsetTop = getElementOffset(targetElement).top
let containerOffsetTop = getElementOffset(containerElement).top
let scrollTarget = targetOffsetTop + ( containerElement.scrollTop - containerOffsetTop)
scrollTarget += offset
scroll(containerElement, scrollTarget, duration)
}
export const scrollWindowToElement = function(targetElement, duration, offset) {
if (duration == null) { duration = 1000 }
if (offset == null) { offset = 0 }
let scrollTarget = getElementOffset(targetElement).top
scrollTarget += offset
scrollWindow(scrollTarget, duration)
}
function scroll(containerElement, scrollTarget, duration) {
let scrollStep = scrollTarget / (duration / 15)
let interval = setInterval(() => {
if ( containerElement.scrollTop < scrollTarget ) {
containerElement.scrollTop += scrollStep
} else {
clearInterval(interval)
}
},15)
}
function scrollWindow(scrollTarget, duration) {
let scrollStep = scrollTarget / (duration / 15)
let interval = setInterval(() => {
if ( window.scrollY < scrollTarget ) {
window.scrollBy( 0, scrollStep )
} else {
clearInterval(interval)
}
},15)
}
function getElementOffset(element) {
let de = document.documentElement
let box = element.getBoundingClientRect()
let top = box.top + window.pageYOffset - de.clientTop
let left = box.left + window.pageXOffset - de.clientLeft
return { top: top, left: left }
}
我就是这样做的。
document.querySelector('scrollHere').scrollIntoView({ behavior: 'smooth' })
适用于任何浏览器。
它可以很容易地包装成函数
function scrollTo(selector) {
document.querySelector(selector).scrollIntoView({ behavior: 'smooth' })
}
下面是一个工作示例$(“.btn”).click(函数){document.getElementById(“scrollHere”).sollIntoView({behavious:“smooth”})}).btn{margin-bottom:500px;}.middle{显示:块;边距底部:500px;颜色:红色;}<script src=“https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js“></script><button class=“btn”>向下滚动</button><h1 class=“middle”>看到了吗</h1><div id=“scrollHere”>到达目的地</div>
Docs
我编写了一个通用函数,可以滚动到jQuery对象、CSS选择器或数值。
示例用法:
// scroll to "#target-element":
$.scrollTo("#target-element");
// scroll to 80 pixels above first element with class ".invalid":
$.scrollTo(".invalid", -80);
// scroll a container with id "#my-container" to 300 pixels from its top:
$.scrollTo(300, 0, "slow", "#my-container");
函数的代码:
/**
* Scrolls the container to the target position minus the offset
*
* @param target - the destination to scroll to, can be a jQuery object
* jQuery selector, or numeric position
* @param offset - the offset in pixels from the target position, e.g.
* pass -80 to scroll to 80 pixels above the target
* @param speed - the scroll speed in milliseconds, or one of the
* strings "fast" or "slow". default: 500
* @param container - a jQuery object or selector for the container to
* be scrolled. default: "html, body"
*/
jQuery.scrollTo = function (target, offset, speed, container) {
if (isNaN(target)) {
if (!(target instanceof jQuery))
target = $(target);
target = parseInt(target.offset().top);
}
container = container || "html, body";
if (!(container instanceof jQuery))
container = $(container);
speed = speed || 500;
offset = offset || 0;
container.animate({
scrollTop: target + offset
}, speed);
};