javascript图片切换

JavaScript 图片滑动切换效果

作者：cloudgamer　时间： 2009-09-25　文档类型：原创　来自：蓝色理想

第 1 页 JavaScript 图片滑动切换效果 [1]
第 2 页 JavaScript 图片滑动切换效果 [2]

序一（08/07/06）
看到 alibaba 的一个图片切换效果，感觉不错，想拿来用用。但代码一大堆的，看着昏，还是自己来吧。
由于有了做图片滑动展示效果的经验，做这个就容易得多了。
序二（09/03/19）
自写了 Tween缓动之后就很想重新写过这个效果，近来有点时间，终于可以动手了。
除了改成Tween缓动，也改进了程序算法，不过原理还是一样的。

效果预览：

运行代码框
<!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> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>JavaScript 图片滑动切换效果</title> <script type="text/javascript"> var $ = function (id) { return "string" == typeof id ? document.getElementById(id) : id; }; var Extend = function(destination, source) { for (var property in source) { destination[property] = source[property]; } return destination; } var CurrentStyle = function(element){ return element.currentStyle || document.defaultView.getComputedStyle(element, null); } var Bind = function(object, fun) { var args = Array.prototype.slice.call(arguments).slice(2); return function() { return fun.apply(object, args.concat(Array.prototype.slice.call(arguments))); } } var Tween = { Quart: { easeOut: function(t,b,c,d){ return -c * ((t=t/d-1)*t*t*t - 1) + b; } }, Back: { 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; } }, Bounce: { 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; } } } } //容器对象,滑动对象,切换数量 var SlideTrans = function(container, slider, count, options) { this._slider = $(slider); this._container = $(container);//容器对象 this._timer = null;//定时器 this._count = Math.abs(count);//切换数量 this._target = 0;//目标值 this._t = this._b = this._c = 0;//tween参数 this.Index = 0;//当前索引 this.SetOptions(options); this.Auto = !!this.options.Auto; this.Duration = Math.abs(this.options.Duration); this.Time = Math.abs(this.options.Time); this.Pause = Math.abs(this.options.Pause); this.Tween = this.options.Tween; this.onStart = this.options.onStart; this.onFinish = this.options.onFinish; var bVertical = !!this.options.Vertical; this._css = bVertical ? "top" : "left";//方向 //样式设置 var p = CurrentStyle(this._container).position; p == "relative" || p == "absolute" || (this._container.style.position = "relative"); this._container.style.overflow = "hidden"; this._slider.style.position = "absolute"; this.Change = this.options.Change ? this.options.Change : this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count; }; SlideTrans.prototype = { //设置默认属性 SetOptions: function(options) { this.options = {//默认值 Vertical: true,//是否垂直方向（方向不能改） Auto: true,//是否自动 Change: 0,//改变量 Duration: 50,//滑动持续时间 Time: 10,//滑动延时 Pause: 2000,//停顿时间(Auto为true时有效) onStart: function(){},//开始转换时执行 onFinish: function(){},//完成转换时执行 Tween: Tween.Quart.easeOut//tween算子 }; Extend(this.options, options || {}); }, //开始切换 Run: function(index) { //修正index index == undefined && (index = this.Index); index < 0 && (index = this._count - 1) || index >= this._count && (index = 0); //设置参数 this._target = -Math.abs(this.Change) * (this.Index = index); this._t = 0; this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]); this._c = this._target - this._b; this.onStart(); this.Move(); }, //移动 Move: function() { clearTimeout(this._timer); //未到达目标继续移动否则进行下一次滑动 if (this._c && this._t < this.Duration) { this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration))); this._timer = setTimeout(Bind(this, this.Move), this.Time); }else{ this.MoveTo(this._target); this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause)); } }, //移动到 MoveTo: function(i) { this._slider.style[this._css] = i + "px"; }, //下一个 Next: function() { this.Run(++this.Index); }, //上一个 Previous: function() { this.Run(--this.Index); }, //停止 Stop: function() { clearTimeout(this._timer); this.MoveTo(this._target); } }; </script> </head> <body> <style type="text/css"> .container, .container img{280px; height:200px;} .container{border:1px solid #333;} .container img{border:0;} </style> <div class="container" id="idContainer"> <table id="idSlider" border="0" cellpadding="0" cellspacing="0"> <tr> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2009/01/06/Tween.html"><img src="/articleimg/2009/09/7031/r_rt_1.jpg"/></a></td> </tr> <tr> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/07/21/ImgCropper.html"><img src="/articleimg/2009/09/7031/r_rt_5.jpg"/></a></td> </tr> <tr> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/11/17/Drag.html"><img src="/articleimg/2009/09/7031/r_rt_3.jpg"/></a></td> </tr> </table> </div> <br /> <br /> <style type="text/css"> .num{ position:absolute; right:5px; bottom:5px;} .num li{ float: left; list-style:none; color: #fff; text-align: center; line-height: 16px; 16px; height: 16px; font-family: Arial; font-size: 12px; cursor: pointer; margin: 1px; border: 1px solid #707070; background-color: #060a0b; } .num li.on{ line-height: 18px; 18px; height: 18px; font-size: 14px; border: 0; background-color: #ce0609; font-weight: bold; } </style> <div class="container" id="idContainer2"> <table id="idSlider2" border="0" cellpadding="0" cellspacing="0"> <tr> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2009/03/11/color.html"><img src="/articleimg/2009/09/7031/r_4.jpg"/></a></td> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/12/24/Slider.html"><img src="/articleimg/2009/09/7031/r_3.jpg"/></a></td> <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/12/03/Resize.html"><img src="/articleimg/2009/09/7031/r_rt_2.jpg"/></a></td> </tr> </table> <ul class="num" id="idNum"> </ul> </div> <br /> <div> <input id="idAuto" type="button" value="停止" /> <input id="idPre" type="button" value="<<" /> <input id="idNext" type="button" value=">>" /> <select id="idTween"> <option value="0">默认缓动</option> <option value="1">方式1</option> <option value="2">方式2</option> </select> </div> <script> new SlideTrans("idContainer", "idSlider", 3).Run(); /////////////////////////////////////////////////////////// var forEach = function(array, callback, thisObject){ if(array.forEach){ array.forEach(callback, thisObject); }else{ for (var i = 0, len = array.length; i < len; i++) { callback.call(thisObject, array[i], i, array); } } } var st = new SlideTrans("idContainer2", "idSlider2", 3, { Vertical: false }); var nums = []; //插入数字 for(var i = 0, n = st._count - 1; i <= n;){ (nums[i] = $("idNum").appendChild(document.createElement("li"))).innerHTML = ++i; } forEach(nums, function(o, i){ o.onmouseover = function(){ o.className = "on"; st.Auto = false; st.Run(i); } o.onmouseout = function(){ o.className = ""; st.Auto = true; st.Run(); } }) //设置按钮样式 st.onStart = function(){ forEach(nums, function(o, i){ o.className = st.Index == i ? "on" : ""; }) } $("idAuto").onclick = function(){ if(st.Auto){ st.Auto = false; st.Stop(); this.value = "自动"; }else{ st.Auto = true; st.Run(); this.value = "停止"; } } $("idNext").onclick = function(){ st.Next(); } $("idPre").onclick = function(){ st.Previous(); } $("idTween").onchange = function(){ switch (parseInt(this.value)){ case 2 : st.Tween = Tween.Bounce.easeOut; break; case 1 : st.Tween = Tween.Back.easeOut; break; default : st.Tween = Tween.Quart.easeOut; } } st.Run(); </script> </body> </html>

[Ctrl+A 全部选择提示：你可先修改部分代码，再按运行]

程序说明

原理就是通过不断设置滑动对象的left(水平切换)和top(垂直切换)来实现图片切换的动态效果。

首先需要一个容器，程序会自动设置容器overflow为hidden，如果不是相对或绝对定位会同时设置position为relative，
滑动对象会设置为绝对定位：

var p = CurrentStyle(this._container).position;
p == "relative" || p == "absolute" || (this._container.style.position = "relative");
this._container.style.overflow = "hidden";
this._slider.style.position = "absolute";

如果没有设置Change切换参数属性，会自动根据滑动对象获取：

this.Change = this.options.Change ? this.options.Change :
this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count;

执行Run方法就会开始进入切换，其中有一个可选参数用来重新设置要切换的图片索引：

index == undefined && (index = this.Index);
index < 0 && (index = this._count - 1) || index >= this._count && (index = 0);
== undefined && (index = this.Index);
index < 0 && (index = this._count - 1) || index >= this._count && (index = 0);

之后就到设置使用 tween缓动时需要的参数了，
包括_target(目标值)、_t(时间)、_b(初始值)和_c(变化量)：

this._target = -Math.abs(this.Change) * (this.Index = index);
this._t = 0;
this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]);
this._c = this._target - this._b;

还有Duration(持续时间)是自定义属性。

参数设置好后就执行Move程序开始移动了。
里面很简单，首先判断_c是否有值（等于0表示不需要移动）和_t是否到达Duration，
未满足条件就继续移动，否则直接移动到目标值并进行下一次切换：

if (this._c && this._t < this.Duration) {
    this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration)));
    this._timer = setTimeout(Bind(this, this.Move), this.Time);
}else{
    this.MoveTo(this._target);
    this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause));

使用说明

实例化需要3个参数，分别是容器对象，滑动对象和切换数量，之后可以直接执行Run方法运行：

new SlideTrans("idContainer", "idSlider", 3).Run();

还有以下可选属性：

Vertical: true,//是否垂直方向（方向不能改）
Auto: true,//是否自动
Change: 0,//改变量
Duration: 50,//滑动持续时间
Time: 10,//滑动延时
Pause: 2000,//停顿时间(Auto为true时有效)
onStart: function(){},//开始转换时执行
onFinish: function(){},//完成转换时执行
Tween: Tween.Quart.easeOut//tween算子

其中Vertical初始化后就不能修改，Tween算子可参照这里的缓动效果选择（实例中选了其中3个）。

还有提供了以下方法：

Next: 切换下一个
Previous: 切换上一个
Stop: 停止自动切换
还有上面说到的Run

程序代码：

代码拷贝框
var SlideTrans = function(container, slider, count, options) { this._slider = $(slider); this._container = $(container);//容器对象 this._timer = null;//定时器 this._count = Math.abs(count);//切换数量 this._target = 0;//目标值 this._t = this._b = this._c = 0;//tween参数 this.Index = 0;//当前索引 this.SetOptions(options); this.Auto = !!this.options.Auto; this.Duration = Math.abs(this.options.Duration); this.Time = Math.abs(this.options.Time); this.Pause = Math.abs(this.options.Pause); this.Tween = this.options.Tween; this.onStart = this.options.onStart; this.onFinish = this.options.onFinish; var bVertical = !!this.options.Vertical; this._css = bVertical ? "top" : "left";//方向 //样式设置 var p = CurrentStyle(this._container).position; p == "relative" || p == "absolute" || (this._container.style.position = "relative"); this._container.style.overflow = "hidden"; this._slider.style.position = "absolute"; this.Change = this.options.Change ? this.options.Change : this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count; }; SlideTrans.prototype = { //设置默认属性 SetOptions: function(options) { this.options = {//默认值 Vertical: true,//是否垂直方向（方向不能改） Auto: true,//是否自动 Change: 0,//改变量 Duration: 50,//滑动持续时间 Time: 10,//滑动延时 Pause: 2000,//停顿时间(Auto为true时有效) onStart: function(){},//开始转换时执行 onFinish: function(){},//完成转换时执行 Tween: Tween.Quart.easeOut//tween算子 }; Extend(this.options, options || {}); }, //开始切换 Run: function(index) { //修正index index == undefined && (index = this.Index); index < 0 && (index = this._count - 1) || index >= this._count && (index = 0); //设置参数 this._target = -Math.abs(this.Change) * (this.Index = index); this._t = 0; this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]); this._c = this._target - this._b; this.onStart(); this.Move(); }, //移动 Move: function() { clearTimeout(this._timer); //未到达目标继续移动否则进行下一次滑动 if (this._c && this._t < this.Duration) { this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration))); this._timer = setTimeout(Bind(this, this.Move), this.Time); }else{ this.MoveTo(this._target); this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause)); } }, //移动到 MoveTo: function(i) { this._slider.style[this._css] = i + "px"; }, //下一个 Next: function() { this.Run(++this.Index); }, //上一个 Previous: function() { this.Run(--this.Index); }, //停止 Stop: function() { clearTimeout(this._timer); this.MoveTo(this._target); } };
[Ctrl+A 全部选择然后拷贝]

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