JavaScript实现许愿墙效果：html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style> body p { margin: 0; } .paper { position: fixed; left: 200px; top: 200px; width: 200px; height: 200px; padding: 20px; background: yellow; border-radius: 5px; box-sizing: border-box; cursor: pointer; } .close { display: block; width: 20px; height: 20px; border: 1px solid #ccc; border-radius: 50%; position: absolute; top: 5px; right: 5px; text-align: center; background: #008c8c; } .inpWords { width: 300px; height: 50px; border: 1px solid #ccc; border-radius: 5px; box-sizing: border-box; padding: 20px; position: fixed; left: 0; right: 0; margin: auto; bottom: 10px; line-height: 50px; font-size: 20px; } </style>
</head>
<body>
<div class="wall">
<!-- <div class="paper">
<p>Lorem ipsum dolor sit amet.</p>
<span class="close">X</span>
</div> -->
<input type="text" class="inpWords" placeholder="许个愿吧">
</div>
<script>
var paperWidth = 200, paperHeight = 200; //愿望签的宽度和高度
var zIndex = 1; //愿望签层叠关系值
var viewWidth = document.documentElement.clientwidth, //记录初始化时浏览器可视窗口的宽度
viewHeight = document.documentElement.clientHeight; //记录初始化时浏览器可视窗口的高度
var hope = document.querySelector(".inpWords"); var wall = document.querySelector(".wall"); hope.onblur = function () { //输入框失去焦点，建立愿望签
createHope(hope.value); } hope.onkeydown = function (e) { //按下回车键也能够建立愿望签
if (e.key === "Enter") { createHope(hope.value); } } window.onmousedown = function (e) { //为愿望签注册鼠标事件
var divHope = getHopeDiv(e.target); //获取到点击的愿望签的dom对象
if (!divHope) { //点击的不是愿望签
return; } divHope.style.zIndex = zIndex; //拖拽的愿望签能够覆盖其余愿望签
zIndex++; var div = window.getComputedStyle(divHope); var hopeLeft = parseFloat(div.left); var hopeTop = parseFloat(div.top); var pageX = e.pageX; var pageY = e.pageY; window.onmousemove = function (e) { //移动愿望签
var disX = e.pageX - pageX; var disY = e.pageY - pageY; var newLeft = hopeLeft + disX; var newTop = hopeTop + disY; //愿望签移动的边界限制，不能超出浏览器视口
if (newLeft < 0) { //最左
newLeft = 0; } if (newLeft > document.documentElement.clientWidth - paperWidth) { //最右
newLeft = document.documentElement.clientWidth - paperWidth; //浏览器视口宽度 - 愿望签宽度
} if (newTop < 0) { //最上
newTop = 0; } if (newTop > document.documentElement.clientHeight - paperHeight - 80) { //最下
newTop = document.documentElement.clientHeight - paperHeight -
80; //浏览器视口高度 - 愿望签高度 - 底部许愿输入框占用的必定高度80
} divHope.style.left = newLeft + "px"; divHope.style.top = newTop + "px"; } window.onmouseup = window.onmouseleave = function () { //鼠标按键抬起或离开愿望签，愿望签不在移动
window.onmousemove = null; } } //注册点击关闭愿望签事件
window.onclick = function (e) { if (e.target.parentElement && e.target.parentElement.className === "paper" && e.target.tagName ===
"SPAN") { e.target.parentElement.remove(); } } //愿望签的位置随着浏览器可视窗口大小改变
window.onresize = function () { var viewDisX = document.documentElement.clientWidth - viewWidth, //记录浏览器可视宽度的改变量
viewDisY = document.documentElement.clientHeight - viewHeight; //记录浏览器可视高度的改变量
//全部的愿望签都要从新调整位置
for (var i = 0; i < wall.children.length; i++) { var hope = wall.children[i]; var left = parseFloat(hope.style.left); //获取浏览器尺寸改变前，愿望签左上角距离浏览器左边边界的距离
var right = viewWidth - paperWidth - left; //获取浏览器尺寸改变前，愿望签右下角距离浏览器右边边界的距离
var newLeft = left + left / (left + right) * viewDisX; //新的left值 等于以前的left值+按比例变化的值
hope.style.left = newLeft + "px"; var top = parseFloat(hope.style.top); //获取浏览器尺寸改变前，愿望签左上角距离浏览器上边边界的距离
var bottom = viewHeight - paperHeight - top; //获取浏览器尺寸改变前，愿望签右下角距离浏览器下边边界的距离
var newTop = top + top / (top + bottom) * viewDisY;//新的top值 等于以前的top值+按比例变化的值
hope.style.top = newTop + "px"; } viewWidth = document.documentElement.clientWidth; //将当前浏览器可视宽度覆盖以前的值
viewHeight = document.documentElement.clientHeight; //将当前浏览器可视高度覆盖以前的值
} //建立愿望签
function createHope(words) { if (words) { var divWall = document.querySelector(".wall"); var divHope = document.createElement("div"); divHope.className = "paper"; divHope.innerHTML = `<p>${words}</p><span class="close">X</span>`; var maxLeft = document.documentElement.clientWidth - paperWidth; //浏览器视口宽度 - 愿望签宽度
var maxTop = document.documentElement.clientHeight - paperHeight -
80; //浏览器视口高度 - 愿望签高度 - 底部许愿输入框占用的必定高度80
divHope.style.background = `rgb(${getRandom(100, 200)},${getRandom(100, 200)},${getRandom(100, 200)})`; //愿望签背景色随机生成
divHope.style.left = getRandom(0, maxLeft) + "px"; divHope.style.top = getRandom(0, maxTop) + "px"; divWall.appendChild(divHope); hope.value = ""; } } //得到一个[min, max]区间的随机数
function getRandom(min, max) { return Math.floor(Math.random() * (max + 1 - min)) + min; } //获取到鼠标点击的愿望签dom对象
function getHopeDiv(dom) { if (dom.className === "paper") { //事件源是愿望签的div
return dom; } else if (dom.parentElement && dom.parentElement.className === "paper" && dom.tagName ===
"P") { //点击的是div里面的P元素
return dom.parentElement; } } //初始化的时候，先建立两个愿望签
function initWall() { var hopeArray = ["梦想成真", "身体健康"]; hopeArray.forEach(function (item) { createHope(item); }); } initWall(); </script>
</body>
</html>
HTML + CSS + JavaScript代码都放在了同一个文件里浏览器
实现功能介绍：app
1.初始化自动生成两个愿望签dom
2.输入框失去焦点或者按回车键，会生成愿望签ide
3.点击关闭会删除愿望签spa
4.能够拖动愿望签，而且不能拖出可视窗口code
5.根据可视窗口的大小，按比例改变愿望签在可视窗口中的位置htm
展现效果：对象
实现功能5的时候会有些困难，下面讲解一下如何获得比例，以下图blog
view是浏览器可视窗口，newView是浏览器放大后的可视窗口，
left是div元素距离浏览器左边的距离，right是div元素距离浏览器右边的距离
newleft是div元素距离浏览器放大后左边的距离，newright是div元素距离浏览器放大后右边的距离
view.width是浏览器的可视窗口宽度，newView.width是浏览器放大后可视窗口的宽度
咱们能够获得如下公式
(newleft + newright) - (left + right) = newView.width - view.width
left和right是按比例放大的，全部浏览器放大后增长的宽度，要按比例分配给newleft和newright
因此，
left / (left + right) * (newView.width - view.width) = newleft - left;
因此，
newleft = left / (left + right) * (newView.width - view.width) +left;