var Tween = {
linear: function (t, b, c, d){
return c*t/d + b;
},
easeIn: function(t, b, c, d){
return c*(t/=d)*t + b;
},
easeOut: function(t, b, c, d){
return -c *(t/=d)*(t-2) + b;
},
easeBoth: function(t, b, c, d){
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){
return c*(t/=d)*t*t*t + b;
},
easeOutStrong: function(t, b, c, d){
return -c * ((t=t/d-1)*t*t*t - 1) + b;
},
easeBothStrong: function(t, b, c, d){
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){
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){
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){
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 = 2.70158; //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){
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;
}
};
/* 当css的参数个数小于3，获取否则 设置 */
function css(el,attr,val) {
if(arguments.length < 3) {
var val = 0;
if(el.currentStyle) {
val = el.currentStyle[attr];
} else {
val = getComputedStyle(el)[attr];
}
if(attr == "opacity") {
val*=100;
}
return parseFloat(val);
}
if(attr == "opacity") {
el.style.opacity = val/100;
el.style.filter = "alpha(opacity = "+val+")";
} else {
el.style[attr] = val + "px";
}
}
/*动画Tween效果*/
function mTween(el,target,time,type,callBack) {
clearInterval(el.timer);
var t = 0;
var b = {};
var c = {};
var d = time/20;
for(var s in target) {
b[s] = css(el,s);
c[s] = target[s] - b[s];
}
el.timer = setInterval(function(){
t++;
if(t>d) {
clearInterval(el.timer);
/*if(callBack) {
callBack()
}*/
callBack&&callBack(); //回调函数 动画执行完了以后，要执行的内容 ，类型 function
} else {
for(var s in target) {
var val = Tween[type](t,b[s],c[s],d);
css(el,s,val);
}
}
},20);
}
/*
t:执行至第几次
b:起始值
c:差值(目标点和起始值的差值)
d:执行总次数
return本次应该在的位置
linear匀速
easeIn加速
easeOut减速
easeBoth先加速后减速
easeInStrong二次方加速
easeOutStrong二次方减速
easeBothStrong二次方先加速后减速
elasticIn弹性在开始方向
elasticout弹性在结束方向
elasticBoth弹性开始和结束都有
backIn回弹在开始方向
backOut回弹在结束方向
backBoth回弹开始和结束都有
bounceIn碰撞在开始方向
bounceOut碰撞在结束方向
bounceBoth碰撞开始和结束都有
*/
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