JS简单动画封装
JS动画，实质是对DOM样式的改变。只要把主流浏览器DOM元素的属性方法搞清楚，做JS动画并不算难。网上也有很多封装好的JS动画库，但大多因为功能过于完善，而至于代码量大动辄过千行，不宜在小项目中使用。这里自己封装了一个很轻量的动画库，主要功能都已实现。难免有疏漏之处，还请大家多多指教。
这里先说明一下功能和用法，以及注意点，随后是一个很简单的可运行示例。
用法及注意事项：
anim(elemId, cssObj, time, animType, funObj)
参数说明：
elemId （必选）需要施加动画效果的元素id
cssObj （必选）动画结束时的样式，对象类型，键值对形式，
其中键是能直接用在JS中的“驼峰”形式的css属性，而不是原来的css属性。
例如：{ marginLeft: '200px', top: '200px', borderWidth: '8px'}
time （必选）动画持续时间（单位ms）
animType （可选）默认为线性变化，代码里的Tween类型包含可选的其他参数
funObj （可选）如果要此选项，需要加入开始和结束时候执行的函数。
形如：{ el为elemId所指向的元素
start: function (el) { el.innerHTML = 'start!'; },
complete: function (el) { el.innerHTML = 'Completed!'; }
}
几点注意事项：
1、没有做低版本浏览器兼容，支持IE8+、FF、chrome、safari、opera
2、注意用能直接用在JS中的“驼峰”形式的css属性（本来应把css转“驼峰”形式，
但是基本所有JS程序员都能直接写出驼峰形式，所以没转）
3、如果需要把动画应用到绝对定位（position:absolute;）元素上，
需要注意在这些元素上设置CSS的方法。
例如：设置top和marginTop，对于绝对定位元素，应该设置top而不是marginTop，
更不应该将二者混合使用，因为二者的参考点是不一样的，同时设置很容易造成混乱。
所以，这里也不支持同时设置二者。
其他相似的同理（left和marginLeft、right和marginRight）
同时设置top和bottom、left和right也不支持。
4、引用了Tween缓动算法，支持线性、渐入渐出等多种变化方式。
5、“动画队列”功能尚未实现，此版本为初级版本，疏漏之处还请多多指正。
<!DOCTYPE HTML>
<html>
<head>
<title></title>
<style type="text/css">
#container{ border:1px solid #000; width:500px; height:400px;}
#aa{ border:1px solid #000; width:100px; height:40px; background-color:#0f0;
position:absolute; left:50px; top:50px; }
#bb{ border:1px solid #000; width:500px; height:40px; margin-top:100px;}
#cc{ border:1px solid #000; width:500px; height:40px;}
</style>
</head><body>
<div id="container">
<input id="Abegin" type="button" value="开始" />
<input id="Apause" type="button" value="暂停" />
<input onclick="location.reload()" type="button" value="刷新网页" />
<div id="aa"><br /></div>
<div id="bb">dfdfddfsd</div>
<div id="cc">gregreger</div>
</div>
<script type="text/javascript">
(function () {
var Tween = {
Linear: function (t, b, c, d) { return c * t / d + b; },
Quad: {
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;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return c / 2 * t * t + b;
return -c / 2 * ((--t) * (t - 2) - 1) + b;
}
},
Cubic: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t + b;
},
easeOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t + 1) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return c / 2 * t * t * t + b;
return c / 2 * ((t -= 2) * t * t + 2) + b;
}
},
Quart: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t * t + b;
},
easeOut: function (t, b, c, d) {
return -c * ((t = t / d - 1) * t * t * t - 1) + b;
},
easeInOut: 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;
}
},
Quint: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t * t * t + b;
},
easeOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
},
easeInOut: function (t, b, c, d) {
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 (t, b, c, d) {
return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
},
easeOut: function (t, b, c, d) {
return c * Math.sin(t / d * (Math.PI / 2)) + b;
},
easeInOut: function (t, b, c, d) {
return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
}
},
Expo: {
easeIn: function (t, b, c, d) {
return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
},
easeOut: function (t, b, c, d) {
return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
},
easeInOut: function (t, b, c, d) {
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 (t, b, c, d) {
return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
},
easeOut: function (t, b, c, d) {
return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
},
easeInOut: function (t, b, c, d) {
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 (t, b, c, d, a, p) {
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 (t, b, c, d, a, p) {
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 (t, b, c, d, a, p) {
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 (t, b, c, d, s) {
if (s == undefined) s = 1.70158;
return c * (t /= d) * t * ((s + 1) * t - s) + b;
},
easeOut: function (t, b, c, d, s) {
if (s == undefined) s = 1.70158;
return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
},
easeInOut: function (t, b, c, d, s) {
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 (t, b, c, d) {
return c - Tween.Bounce.easeOut(d - t, 0, c, d) + b;
},
easeOut: 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 + .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 (t, b, c, d) {
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;
}
}
}
var color = {
sub: function (str, start, len) {
if (len) return str.substring(start, start + len);
else return str.substring(start);
},
hex: function (i) { // 返回16进制颜色表示
if (i < 0) return "00";
else if (i > 255) return "ff";
else { var str = "0" + i.toString(16); return str.substring(str.length - 2); }
},
//获取颜色数据
GetColors: function (sColor) {
sColor = sColor.replace("#", "");
var r, g, b;
if (sColor.length > 3) {
r = color.sub(sColor, 0, 2); g = color.sub(sColor, 2, 2); b = color.sub(sColor, 4, 2);
} else {
r = color.sub(sColor, 0, 1); g = color.sub(sColor, 1, 1); b = color.sub(sColor, 2, 1);
r += r; g += g; b += b;
}
return [parseInt(r, 16), parseInt(g, 16), parseInt(b, 16)];
}
}
var fn = {
getElement: function (id) {
return typeof id == "string" ? document.getElementById(id) : id;
},
objType: function (obj) {
switch (Object.prototype.toString.call(obj)) {
case "[object Object]":
return "Object";
case "[object Number]":
return "Number";
case "[object Array]":
return "Array";
}
},
getStyle: function (elem, name) { //
var w3style;
if (document.defaultView) {
var style = document.defaultView.getComputedStyle(elem, null);
name == "borderWidth" ? name = "borderLeftWidth" : name; // 解决标准浏览器解析问题
w3style = name in style ? style[name] : style.getPropertyValue(name);
w3style == "auto" ? w3style = "0px" : w3style;
}
return elem.style[name] ||
(elem.currentStyle && (elem.currentStyle[name] == "auto" ? "0px" : elem.currentStyle[name])) || w3style;
},
getOriCss: function (elem, cssObj) { // 此处只能获取属性值为数值类型的style属性
var cssOri = [];
for (var prop in cssObj) {
if (!cssObj.hasOwnProperty(prop)) continue;
//if (prop != "opacity") cssOri.push(parseInt(fn.getStyle(elem, prop)));
//else cssOri.push(100 * fn.getStyle(elem, prop));
if (fn.getStyle(elem, prop) == "transparent" || /^#|rgb\(/.test(fn.getStyle(elem, prop))) {
if (fn.getStyle(elem, prop) == "transparent") {
cssOri.push([255, 255, 255]);
}
if (/^#/.test(fn.getStyle(elem, prop))) {
cssOri.push(color.GetColors(fn.getStyle(elem, prop)));
}
if (/^rgb\(/.test(fn.getStyle(elem, prop))) {
//cssOri.push([fn.getStyle(elem, prop).replace(/^rgb\(\)/g, "")]);
var regexp = /^rgb\(([0-9]{0,3}),\s([0-9]{0,3}),\s([0-9]{0,3})\)/g;
var re = fn.getStyle(elem, prop).replace(regexp, "$1 $2 $3").split(" ");
//cssOri.push(re); // re为字符串数组
cssOri.push([parseInt(re[0]), parseInt(re[1]), parseInt(re[2])]);
}
} else if (prop == "opacity") {
cssOri.push(100 * fn.getStyle(elem, prop));
} else {
cssOri.push(parseInt(fn.getStyle(elem, prop)));
}
}
return cssOri;
},
getEndCss: function (cssobj) {
var cssEnd = [];
for (var prop in cssobj) {
if (!cssobj.hasOwnProperty(prop)) continue;
//if (prop != "opacity") cssEnd.push(parseInt(cssobj[prop]));
//else cssEnd.push(100 * cssobj[prop]);
if (prop == "opacity") {
cssEnd.push(100 * cssobj[prop]);
} else if (/^#/.test(cssobj[prop])) {
cssEnd.push(color.GetColors(cssobj[prop]));
} else {
cssEnd.push(parseInt(cssobj[prop]));
}
}
return cssEnd;
}
}
function _anim(/*elemId, cssObj, time, animType, funObj*/) {
this.init.apply(this, arguments[0]);
}
_anim.prototype = {
init: function () {
this.elem = fn.getElement(arguments[0]);
this.cssObj = arguments[1];
this.cssOri = fn.getOriCss(this.elem, arguments[1]);
this.cssEnd = fn.getEndCss(arguments[1]);
this.durtime = arguments[2];
this.animType = "Tween.Linear";
this.funObj = null;
this.start = false;
this.complete = false;
this.onPause = false;
this.onRestart = false;
if (arguments.length < 3) {
throw new Error("至少要传入3个参数");
} else if (arguments.length == 4) {
if (fn.objType(arguments[3]) == "Object") {
this.funObj = arguments[3];
for (var p in this.funObj) {
if (p.toString() == "start") this.start = true;
if (p.toString() == "complete") this.complete = true;
}
}
if (typeof (arguments[3]) == "string") {
this.animType = arguments[3];
}
} else if (arguments.length == 5) {
this.animType = arguments[3];
if (fn.objType(arguments[4]) == "Object") {
this.funObj = arguments[4];
for (var p in this.funObj) {
if (p.toString() == "start") this.start = true;
if (p.toString() == "complete") this.complete = true;
}
}
}
this.startAnim();
},
startAnim: function () {
if (this.start) this.funObj["start"].call(this, this.elem);
var that = this;
var t = 0;
var props = [];
for (var pro in this.cssObj) {
if (!this.cssObj.hasOwnProperty(pro)) continue;
props.push(pro);
}
var tt = new Date().getTime();
clearInterval(this.timer);
this.timer = setInterval(function () {
if (that.onPause) {
clearInterval(that.timer);
return;
}
if (t < that.durtime / 10) {
t++;
for (var i = 0; i < props.length; i++) {
var b, c;
fn.objType(that.cssOri[i]) != "Array" && (b = that.cssOri[i]); //开始值
fn.objType(that.cssEnd[i]) != "Array" && (c = that.cssEnd[i] - that.cssOri[i]); // 变化量
var d = that.durtime / 10; // 持续时间
if (fn.objType(that.cssOri[i]) == "Array" && fn.objType(that.cssEnd[i]) == "Array") {
var b1 = that.cssOri[i][0], b2 = that.cssOri[i][1], b3 = that.cssOri[i][2];
var c1 = that.cssEnd[i][0] - that.cssOri[i][0],
c2 = that.cssEnd[i][1] - that.cssOri[i][1],
c3 = that.cssEnd[i][2] - that.cssOri[i][2];
var r = color.hex(Math.ceil((eval(that.animType))(t, b1, c1, d))),
g = color.hex(Math.ceil((eval(that.animType))(t, b2, c2, d))),
b = color.hex(Math.ceil((eval(that.animType))(t, b3, c3, d)));
that.elem.style[props[i]] = "#" + r + g + b;
} else if (props[i].toString() == "opacity") {
that.elem.style[props[i]] = Math.ceil((eval(that.animType))(t, b, c, d)) / 100;
} else {
that.elem.style[props[i]] = Math.ceil((eval(that.animType))(t, b, c, d)) + "px";
}
}
} else {
for (var i = 0; i < props.length; i++) {
if (fn.objType(that.cssOri[i]) == "Array" && fn.objType(that.cssEnd[i]) == "Array") {
var c1 = that.cssEnd[i][0],
c2 = that.cssEnd[i][1],
c3 = that.cssEnd[i][2];
var r = color.hex(Math.ceil((eval(that.animType))(t, b1, c1, d))),
g = color.hex(Math.ceil((eval(that.animType))(t, b2, c2, d))),
b = color.hex(Math.ceil((eval(that.animType))(t, b3, c3, d)));
that.elem.style[props[i]] = "#" + r + g + b;
} else if (props[i].toString() == "opacity") {
that.elem.style[props[i]] = that.cssEnd[i] / 100;
} else {
that.elem.style[props[i]] = that.cssEnd[i] + "px";
}
}
clearInterval(that.timer);
if (that.complete) that.funObj["complete"].call(that, that.elem);
//alert(new Date().getTime() - tt);
}
}, 10); // 一般要给10毫秒异步调用时间，不能是1
},
pause: function () {
this.onPause = true;
}
} www.2cto.com
window.anim = function () {
return new _anim(arguments);
}
})();
</script>
<script type="text/javascript">
var bbtn = document.getElementById("Abegin"),
pbtn = document.getElementById("Apause");
var a;
bbtn.onclick = function () {
a = anim("aa", {
left: '200px',
top: '200px',
width: '200px',
height: '200px',
backgroundColor: '#f00',
borderWidth: '8px'
}, 4000, 'Tween.Bounce.easeInOut', {
start: function (el) { el.innerHTML = 'start!'; },
complete: function (el) { el.innerHTML = 'Completed!'; }
}
);
}
pbtn.onclick = function () {
a.pause();
}
anim("bb", {
marginTop:'160px',
opacity:0.1,
width: '200px',
height: '200px',
borderWidth: '8px'
}, 2000, 'Tween.Bounce.easeIn', {
start: function (el) { el.innerHTML = 'start!'; },
complete: function (el) { el.innerHTML = 'Completed!'; }
}
);
</script>
</body>
</html>
作者 huajs
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