用到一些封装好的运动函数，主要是定时器
效果为图片和图片的描述定时自动更换
<!DOCTYPE html>
<html><head><meta charset="UTF-8"><title></title><style type="text/css">ul,li,p,h3 {padding: 0;margin: 0;list-style: none;}img {border: none;vertical-align: top;}#bg_box {width: 1000px;height: 590px;margin: 50px auto;position: relative;background: url(img/bg1.jpg) no-repeat;
}.pic {width: 440px;height: 274px;position: absolute;top: 50px;left: 220px;overflow: hidden;}.li_box {width: 1760px;height: 274px;position: absolute;left: 0;}.tags {width: 440px;height: 80px;position: absolute;bottom: -80px;background-image: linear-gradient(0deg, rgba(0, 0, 0, 0.4) 0%, rgba(255, 255, 255, 0) 100%);color: white;padding-left: 20px;padding-top: 15px;box-sizing: border-box;}.tags:nth-of-type(1) {/*bottom: 0;*/}.img {float: left;width: 440px;height: 274px;}h3 {font: bold 20px/30px "微软雅黑";
}p {font: 16px/30px "微软雅黑";
}</style><script src="tween.js"></script><script src="commom.js"></script><script type="text/javascript">window.onload = function() {//获取元素var liBbox = $('ul')[0];var li = $('li');var tags = $('.tags')var num = 0; //设置初始位置
Change()function Change() {var M = tags[num];MTween(M, 'bottom', 0, 500, 'px', 'linear', function() { //先让描述内容出现num if(num > li.length - 1) { //边界设置。return;}setTimeout(function() {MTween(M, 'bottom', -80, 500, 'px', 'linear', function() { //让描述内容不显示MTween(liBbox, 'left', -num * 440, 800, 'px', 'linear', function() {Change();}); //切换图片
});}, 1000)});}}</script></head><body><section id="bg_box"><div class="pic"><ul class="li_box"><li><img class="img" src="img/a5.gif"></li><li><img class="img" src="img/a6.gif"></li><li><img class="img" src="img/a7.gif"></li><li><img class="img" src="img/a8.gif"></li></ul><div class="tags"><h3 class="title">下雨了~~~</h3><p class="tag">这是一个适合在家睡觉的日子!!</p></div><div class="tags"><h3 class="title">包饺子~~~</h3><p class="tag">一只会居家过日子的小狐狸！！</p></div><div class="tags"><h3 class="title">生气了~~~</h3><p class="tag">吃掉好吃的就不生气了！！</p></div><div class="tags"><h3 class="title">出发了~~~</h3><p class="tag">来一段说走就走的旅行!!</p></div></div></section></body></html>commom.js
function MTween(obj,attr,end,duration,unit,way,callBack){if(obj.isAnim) return;//obj开始运动了 自定义属性obj.isAnim = true;if(!way){ //如果用户没有选择运动方式就默认匀速way = 'linear';}if(!unit){ //如果用户没有选择运动方式就默认匀速unit = '';}var start = parseFloat(getStyle(obj,attr));//起始位置
// var end = 1000;//目标点
// var duration = 1000;//动画执行的总时间 单位是毫秒var startTime = Date.now();var s = end - start; //总路程// var v = s/duration; //计算出来的速度//每次20ms走一帧
clearInterval(timer);var timer = 0;timer = setInterval(function(){var endTime = Date.now();//计算出当前时间var t = endTime-startTime;if(t>=duration){t = duration;clearInterval(timer);//到达目标点要清除定时器
}// obj.style[attr] = t*s/duration start 'px';
// console.log(Tween[way](t,start,s,duration))obj.style[attr] = Tween[way](t,start,s,duration) unit;//透明度的兼容处理if(attr=='opacity'){obj.style.filter = 'Alpha(opacity=' Tween[way](t,start,s,duration)*100 ')';}if(t==duration){obj.isAnim = false;//等到上一个动画完成 然后再调用if(callBack){callBack();}}},20);
}tween.js
/*
* t : time 已过时间 当前时间-初始时间
* b : begin 起始值
* c : count 总的运动值 总路程
* d : duration 持续时间 总时间
*
* s = vt; => c = t*c/d 这里只计算总共要运动的路程 ，不包括起始位置
*
* attrVal = t*c/d b;
*
* 曲线方程
*
* http://www.cnblogs.com/bluedream2009/archive/2010/06/19/1760909.html
* *///Tween.linear();var Tween = {linear: function (t, b, c, d){ //匀速return c*t/d b;
},easeIn: function(t, b, c, d){ //加速曲线return c*(t/=d)*t b;
},easeOut: function(t, b, c, d){ //减速曲线return -c *(t/=d)*(t-2) b;
},easeBoth: function(t, b, c, d){ //加速减速曲线if ((t/=d/2) < 1) {return c/2*t*t b;
}return -c/2 * ((--t)*(t-2) - 1) b;
},easeInStrong: function(t, b, c, d){ //加加速曲线return c*(t/=d)*t*t*t b;
},easeOutStrong: function(t, b, c, d){ //减减速曲线return -c * ((t=t/d-1)*t*t*t - 1) b;
},easeBothStrong: function(t, b, c, d){ //加加速减减速曲线if ((t/=d/2) < 1) {return c/2*t*t*t*t b;
}return -c/2 * ((t-=2)*t*t*t - 2) b;
},elasticIn: function(t, b, c, d, a, p){ //正弦衰减曲线（弹动渐入）if (t === 0) { return b; }if ( (t /= d) == 1 ) {return b c; }if (!p) {p=d*0.3; }if (!a || a < Math.abs(c)) {a = c; var s = p/4;} else {var s = p/(2*Math.PI) * Math.asin (c/a);}return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) b;
},elasticOut: function(t, b, c, d, a, p){ //*正弦增强曲线（弹动渐出）if (t === 0) {return b;}if ( (t /= d) == 1 ) {return b c;}if (!p) {p=d*0.3;}if (!a || a < Math.abs(c)) {a = c;var s = p / 4;} else {var s = p/(2*Math.PI) * Math.asin (c/a);}return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) c b;
}, elasticBoth: function(t, b, c, d, a, p){if (t === 0) {return b;}if ( (t /= d/2) == 2 ) {return b c;}if (!p) {p = d*(0.3*1.5);}if ( !a || a < Math.abs(c) ) {a = c; var s = p/4;
}else {var s = p/(2*Math.PI) * Math.asin (c/a);}if (t < 1) {return - 0.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) b;
}return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*0.5 c b;
},backIn: function(t, b, c, d, s){ //回退加速（回退渐入）if (typeof s == 'undefined') {s = 1.70158;}return c*(t/=d)*t*((s 1)*t - s) b;
},backOut: function(t, b, c, d, s){if (typeof s == 'undefined') {s = 3.70158; //回缩的距离
}return c*((t=t/d-1)*t*((s 1)*t s) 1) b;
}, backBoth: function(t, b, c, d, s){if (typeof s == 'undefined') {s = 1.70158; }if ((t /= d/2 ) < 1) {return c/2*(t*t*(((s*=(1.525)) 1)*t - s)) b;
}return c/2*((t-=2)*t*(((s*=(1.525)) 1)*t s) 2) b;
},bounceIn: function(t, b, c, d){ //弹球减振（弹球渐出）return c - Tween['bounceOut'](d-t, 0, c, d) b;}, bounceOut: function(t, b, c, d){//*if ((t/=d) < (1/2.75)) {return c*(7.5625*t*t) b;} else if (t < (2/2.75)) {return c*(7.5625*(t-=(1.5/2.75))*t 0.75) b;} else if (t < (2.5/2.75)) {return c*(7.5625*(t-=(2.25/2.75))*t 0.9375) b;
}return c*(7.5625*(t-=(2.625/2.75))*t 0.984375) b;
}, bounceBoth: function(t, b, c, d){if (t < d/2) {return Tween['bounceIn'](t*2, 0, c, d) * 0.5 b;}return Tween['bounceOut'](t*2-d, 0, c, d) * 0.5 c*0.5 b;}
}
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