<html><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <meta name="apple-mobile-web-app-capable" content="yes"> <meta name="format-detection" content="telephone=no, email=no"> <title>snowflake</title> <script type="text/javascript" src="http://w3school.com.cn/jquery/jquery-1.11.1.min.js"></script> <style type="text/css"> body { padding: 0; margin: 0; background-color: #333; font-size: 14px; color: #BCBCBC; } input { border: solid 0px #DDD; border-radius: 5px; padding: 5px 10px; width: 120px; } button { border: solid 0px #CCC; border-radius: 5px; background-color: #FFF; padding: 5px 10px; } #sky { width: 100%; max-width: 640px; height: 100%; background-color: #A39; margin: 0 auto; position: relative; overflow: hidden; } .snowflake { width: 50px; height: 50px; border-radius: 50px; background-color: rgba(255, 255, 255, 0.5); position: absolute; top: 10px; left: 100px; display: inline-block; transition: top 2s; -moz-transition: top 2s;/* Firefox 4 */ -webkit-transition: top 2s;/* Safari 和 Chrome */ -o-transition: top 2s; transition-timing-function: cubic-bezier(0.25,0.1,0.25,1); -moz-transition-timing-function: cubic-bezier(0.25,0.1,0.25,1); -webkit-transition-timing-function: cubic-bezier(0.25,0.1,0.25,1); -o-transition-timing-function: cubic-bezier(0.25,0.1,0.25,1); } #operate { text-align: right; } #operate div { margin: 10px; } </style></head><body> <div id="sky"></div> <div id="operate"> <div> <label>下雪频率(ms): <input name="rate" type="number" min="1" /></label> </div> <div> <label>融化时间(ms): <input name="melt" type="number" min="0" /></label> </div> <div> <button id="start-or-stop" onclick="startOrStop()">start</button> </div> </div> <script type="text/javascript"> var $sky = $('#sky'); var maxTop = $sky.height() - 5;// 地面高度值(px) var rate = 60;// 飘落频率(ms) var flakeSize = 10;// 单片雪花宽高值(px) var melt = 2000;// 融化时间(ms) // 初始化雪花 function snowflake(size, alpha, top, left) { var s = document.createElement('div'); $(s).css({ 'width': size, 'height': size, 'border-radius': size, 'background-color': 'rgba(255,255,255,' + alpha + ')', 'top': -50, 'left': left, }).addClass('snowflake'); return s; } // 雪花飘落并融化 function dift($s) { $s.css('top', maxTop + (flakeSize - $s.width()) / 2); setTimeout(function() { $s.remove(); }, 2000 + melt); } // 开始动画 var animateId = -1; var it = false; function start() { if(!it) { it = setInterval(function() { // 初始化雪花 var id = 's_' + (++animateId); var size = Math.random() * flakeSize + 2; var alpha = Math.random() * 0.7 + 0.1; var left = Math.random() * $(window).width(); var s = snowflake(size, alpha, 0, left); var $s = $(s).attr('id', id); $sky.get(0).appendChild(s); // 雪花飘落 setTimeout(function() { dift($s); }, 100); if(animateId > 10000) {// 避免越界 animateId = 0; } }, rate); $('#start-or-stop').html('stop'); } } start(); // 停止动画 function stop() { clearInterval(it); it = false; $('#start-or-stop').html('start'); } // 开始或暂停动画 function startOrStop() { if(!it) { start(); } else { stop(); } } // 重启动画 function restart() { stop(); start(); } $(function() { // 监听rate输入框 var minRate = 1, maxRate = 3000; $('input[name="rate"]').val(rate).on('change', function() { rate = parseInt($(this).val()); if(rate < minRate) { rate = minRate; $(this).val(rate); } else if(rate > maxRate) { rate = maxRate; $(this).val(rate); } restart(); }).prop({ min: minRate, max: maxRate }); // 监听melt输入框 var minMalt = 0, maxMelt = 100000; $('input[name="melt"]').val(melt).on('change', function() { melt = parseInt($(this).val()); if(melt < minMalt) { melt = minMalt; $(this).val(melt); } else if(melt > maxMelt) { melt = maxMelt; $(this).val(melt); } restart(); }).prop({ min: minMalt, max: maxMelt }); }); </script></body></html>Copy after login
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