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来源：未知 时间：2016-02-02 17:34 作者：xxadmin 阅读:次
[导读] 原声Javascript基础实列几个最基本的特效， 即：移动，渐变和尺寸变化。 Js中实现动画都是靠setInterval或者setTimeout来实现。setInterval自身就能不断循环来执行计算从而显示新的帧，setTi...
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原声Javascript基础实列几个最基本的特效， 即：移动，渐变和尺寸变化。 Js中实现动画都是靠setInterval或者setTimeout来实现。setInterval自身就能不断循环来执行计算从而显示新的帧，setTimeout是间隔一段时间后仅执行一次，他需要配合函数循环实现，很多人偏爱setTimeout来实现。本文采用setInterval实现。 普通人眼能看到1/24秒，就是说1秒至少24帧，每次移位间隔需要小于1000/24=41.7毫秒，也就说setInterval要每隔至少40毫秒执行一次，一般地，我们采用10毫秒，当然间隔时间越短，客户端执行计算次数就越多，如果你code计算量大则可以适当调长些。 代码如下： <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script type="text/javascript">
/*
t:currentCount 当前执行第t次
b:initPos 初始值
c:targetPos - initPos 发生偏移的距离值
d:count 一共执行d次
效果：http://www.robertpenner.com/easing/easing_demo.html
JavaScript Tween算法及缓动效果 http://www.cnblogs.com/cloudgamer/archive/2009/01/06/tween.html
*/
var Tween = {
Linear: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * t / d + b;
},
Quad: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * (t /= d) * t + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return -c * (t /= d) * (t - 2) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if ((t /= d / 2) < 1) return c / 2 * t * t + b;
return -c / 2 * ((--t) * (t - 2) - 1) + b;
}
},
Cubic: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * (t /= d) * t * t + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * ((t = t / d - 1) * t * t + 1) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if ((t /= d / 2) < 1) return c / 2 * t * t * t + b;
return c / 2 * ((t -= 2) * t * t + 2) + b;
}
},
Quart: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * (t /= d) * t * t * t + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return -c * ((t = t / d - 1) * t * t * t - 1) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if ((t /= d / 2) < 1) return c / 2 * t * t * t * t + b;
return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
}
},
Quint: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * (t /= d) * t * t * t * t + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if ((t /= d / 2) < 1) return c / 2 * t * t * t * t * t + b;
return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
}
},
Sine: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * Math.sin(t / d * (Math.PI / 2)) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
}
},
Expo: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (t == 0) return b;
if (t == d) return b + c;
if ((t /= d / 2) < 1) return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
}
},
Circ: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if ((t /= d / 2) < 1) return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
}
},
Elastic: {
easeIn: function(initPos, targetPos, currentCount, count, a, p) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (t == 0) return b; if ((t /= d) == 1) return b + c; if (!p) p = d * .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;
},
easeOut: function(initPos, targetPos, currentCount, count, a, p) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (t == 0) return b; if ((t /= d) == 1) return b + c; if (!p) p = d * .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);
},
easeInOut: function(initPos, targetPos, currentCount, count, a, p) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (t == 0) return b; if ((t /= d / 2) == 2) return b + c; if (!p) p = d * (.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 -.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) * .5 + c + b;
}
},
Back: {
easeIn: function(initPos, targetPos, currentCount, count, s) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (s == undefined) s = 1.70158;
return c * (t /= d) * t * ((s + 1) * t - s) + b;
},
easeOut: function(initPos, targetPos, currentCount, count, s) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (s == undefined) s = 1.70158;
return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
},
easeInOut: function(initPos, targetPos, currentCount, count, s) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (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;
}
},
Bounce: {
easeIn: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
return c - Tween.Bounce.easeOut(d - t, 0, c, d) + b;
},
easeOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
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 + .75) + b;
} else if (t < (2.5 / 2.75)) {
return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b;
} else {
return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
}
},
easeInOut: function(initPos, targetPos, currentCount, count) {
var b = initPos, c = targetPos - initPos, t = currentCount, d = count;
if (t < d / 2) return Tween.Bounce.easeIn(t * 2, 0, c, d) * .5 + b;
else return Tween.Bounce.easeOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
}
}
}
///------------------------------------------------------------------------------------------------------
Animation = {
timer: 10,
SetOpacity: function(obj, n) {
if (document.all) {
obj.filters.alpha.opacity = n;
}
else {
obj.style.opacity = n / 100;
}
},
fade: function(obj, target, count, Func) {
obj = this.getItself(obj);
var currentCount = 0;
count = Math.abs(count) || 1;
target = target < 0 ? 0 : (target > 100) ? 100 : target;
var init = document.all ? obj.filters.alpha.opacity : window.getComputedStyle(obj, null).opacity * 100;
Func = Func || Tween.Linear;
var opr = this;
var flag = setInterval(function() {
if (currentCount > count) {
clearInterval(flag);
}
else {
currentCount++;
var tmp = Func(init, target, currentCount, count);
opr.SetOpacity(obj, tmp);
//清除小数点的误差
if (Math.abs(tmp - target) < 1) {
opr.SetOpacity(obj, target);
}
}
}
, this.timer);
},
resize: function(obj, targetPos, count, Func) {
obj = this.getItself(obj);
var currentCount = 0;
count = Math.abs(count) || 1;
var initPos = { x: obj.offsetWidth, y: obj.offsetHeight }
Func = Func || Tween.Linear;
targetPos = { x: targetPos.x < 0 ? 0 : targetPos.x, y: targetPos.y < 0 ? 0 : targetPos.y }
var flag = setInterval(function() {
if (currentCount > count) {
clearInterval(flag);
}
else {
currentCount++;
var tmpX = Func(initPos.x, targetPos.x, currentCount, count);
var tmpY = Func(initPos.y, targetPos.y, currentCount, count);
//width值不能小于0，但是算法返回值有可能出现负值
try {
obj.style.width = tmpX + "px";
obj.style.height = tmpY + "px";
}
catch (e) {
}
//清除小数点的误差
if (Math.abs(tmpX - targetPos.x) < 1) {
obj.style.width = targetPos.x + "px";
}
&nb
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