假設我們這裡有1到5五張bmp圖片,那麼控制圖片切換顯示的核心代碼可以為:
<script> var i=1; var img = new Array(); img[0] = "1.bmp"; img[1] = "2.bmp"; img[2] = "3.bmp"; img[3] = "4.bmp"; img[4] = "5.bmp"; function playImg(){ i=i+1; var imgs = document.getElementById("img"); imgs.src =img[i]; if(i>=4){ i=1; } } window.onload = function(){ document.getElementById("img").src="1.bmp"; } </script> <img id="img" src="" width="500" hieght="500" onclick="playImg()" style="cursor:pointer;">
主要體現了一個圖片的切換控制思路,可以用於各種場景,那麼下面我們來看一個復雜一些的實現,能夠控制滑動和停頓事件等具體的實現圖片的滑動切換效果的例子:
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 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 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; } } } } //容器對象,滑動對象,切換數量 var SlideTrans = function(container, slider, count, options) { this._slider = (slider);this.container= (container);//容器對象 this._timer = null;//定時器 this._count = Math.abs(count);//切換數量 this._target = 0;//目標值 this._t = this._b = this._c = 0;//tween參數 this.Index = 0;//當前索引 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 //樣式設置 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 = { //設置默認屬性 SetOptions: function(options) { this.options = {//默認值 Vertical: true,//是否垂直方向(方向不能改) Auto: true,//是否自動 Change: 0,//改變量 Duration: 30,//滑動持續時間 Time: 10,//滑動延時 Pause: 3000,//停頓時間(Auto為true時有效) onStart: function(){},//開始轉換時執行 onFinish: function(){},//完成轉換時執行 Tween: Tween.Quart.easeOut//tween算子 }; Extend(this.options, options || {}); }, //開始切換 Run: function(index) { //修正index index == undefined && (index = this.Index); index < 0 && (index = this._count - 1) || index >= this._count && (index = 0); //設置參數 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(); }, //移動 Move: function() { clearTimeout(this._timer); //未到達目標繼續移動否則進行下一次滑動 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)); } }, //移動到 MoveTo: function(i) { this._slider.style[this._css] = i + "px"; }, //下一個 Next: function() { this.Run(++this.Index); }, //上一個 Previous: function() { this.Run(--this.Index); }, //停止 Stop: function() { clearTimeout(this._timer); this.MoveTo(this._target); } };