slider.names = new Array();
function slider() {
    this.id = slider.names.length;
    slider.names[this.id] = this;
    this.target = document.getElementById(arguments[0]); //第一个参数：被操作div的id
    this.direction = arguments[1]; //第二个参数：div弹出的方向
    this.height = arguments[2]; //第三个参数：div的高度
    this.width = arguments[3]; //第四个参数：div的宽度
    this.step = arguments[4]; //第五个参数：希望动作分解为几步完成
    this.timer = 10 * arguments[5]; //第六个参数：每个动作的间隔时间，10ms为一个单位
    this.startopa = arguments[6]; //第七个参数：div开始的透明度
    this.sparent = this.target.parentNode; //获取操作div的父容器
    this.intervalid = null; //循环定时的id
    this.i = 0; //循环的计数器
    this.status = 0; //slider层的状态：0-可以展开；1-不可以展开
    this.target.style.display = "none"; //先将div隐去
    return this;
}
slider.prototype.initialize = function() {
    this.sparent.style.overflow = "hidden"; //设置父容器overflow
    this.target.style.width = Number(this.width) + 'px'; //设置目标div的宽度
    this.target.style.height = Number(this.height) + 'px'; //设置目标div的高度
    this.target.style.position = ""; //设置目标div的定位方式
    this.target.style.display = ""; //设置目标div的显示方式
    this.target.style.filter = 'Alpha(opacity=' + Number(this.startopa) + ')'; //设置目标div的透明度为初始透明度
    this.target.style.overflow = "hidden"; //设置overflow
    switch (this.direction)//根据弹出方向设定div的margin
    {
        case 1: //left to right
            this.target.style.marginLeft = "-" + this.width + "px";
            break;
        case 2: //top to bottom
            this.target.style.marginTop = "-" + this.height + "px";
            break;
        case 3: //right to left
            this.target.style.marginRight = "-" + this.width + "px";
            break;
    }
}
slider.prototype.show = function() {
    if (this.status == 0)//检查状态是否已经展开
    {
        this.initialize(); //操作div及其父容器的初始化
        this.intervalid = window.setInterval("slider.names[" + this.id + "].cycle()", this.timer); //设置动作循环
    }
}
slider.prototype.hide = function() {
    if (this.status == 1)//检查状态是否已经展开
    {
        this.intervalid = window.setInterval("slider.names[" + this.id + "].decycle()", this.timer); //设置动作循环
    }
}
slider.prototype.cycle = function()	//单步循环动作
{
    var opa = this.target.style.filter.split("=")[1].split(")")[0]//获取目标div的透明度数值
    var opastep = Math.round(((100 - Number(opa)) / this.step) + 2.5); //计算每步增加的透明度
    var nopa = Number(opa) + Number(opastep); //当前透明度
    if (nopa > 100) { this.target.style.filter = 'Alpha(opacity=100)'; } else { this.target.style.filter = 'Alpha(opacity=' + String(nopa) + ')'; } //给div透明度赋值
    switch (this.direction)//根据弹出方向计算和设定div的动作
    {
        case 1: 	//left to right
            var opx = this.target.style.marginLeft.split("px")[0];
            var pxstep = Math.round((this.width / this.step) + 0.5);
            var npx = Number(opx) + Number(pxstep);
            if (npx > 0) { this.target.style.marginLeft = '0px'; } else { this.target.style.marginLeft = String(npx) + 'px'; }
            break;
        case 2: 	//top to bottom
            var opx = this.target.style.marginTop.split("px")[0];
            var pxstep = Math.round((this.height / this.step) + 0.5);
            var npx = Number(opx) + Number(pxstep);
            if (npx > 0) { this.target.style.marginTop = '0px'; } else { this.target.style.marginTop = String(npx) + 'px'; }
            break;
        case 3: 	//right to left
            var opx = this.target.style.marginRight.split("px")[0];
            var pxstep = Math.round((this.width / this.step) + 0.5);
            var npx = Number(opx) + Number(pxstep);
            if (npx > 0) { this.target.style.marginRight = '0px'; } else { this.target.style.marginRight = String(npx) + 'px'; }
            break;
    }
    this.i++	//计数器+1
    if (this.i > (this.step - 1)) { window.clearInterval(this.intervalid); this.i = 0; this.status = 1; } //循环完毕，清除循环定时
}
slider.prototype.decycle = function()	//单步循环动作
{
    var opa = this.target.style.filter.split("=")[1].split(")")[0]//获取目标div的透明度数值
    var opastep = Math.round(((100 - Number(opa)) / this.step) + 2.5) * 2; //计算每步增加的透明度
    var nopa = Number(opa) - Number(opastep); //当前透明度
    if (nopa < this.startopa) { this.target.style.filter = 'Alpha(opacity=' + this.startopa + ')'; } else { this.target.style.filter = 'Alpha(opacity=' + String(nopa) + ')'; } //给div透明度赋值
    switch (this.direction)//根据弹出方向计算和设定div的动作
    {
        case 1: 	//left to right
            var opx = this.target.style.marginLeft.split("px")[0];
            var pxstep = Math.round((this.width / Math.round(this.step * 0.5)) + 0.5);
            var npx = Number(opx) - Number(pxstep);
            if (Math.abs(npx) > this.width + 2) { this.target.style.marginLeft = '-' + this.width + 'px'; } else { this.target.style.marginLeft = String(npx) + 'px'; }
            break;
        case 2: 	//top to bottom
            var opx = this.target.style.marginTop.split("px")[0];
            var pxstep = Math.round((this.height / Math.round(this.step * 0.5)) + 0.5);
            var npx = Number(opx) - Number(pxstep);
            if (Math.abs(npx) > this.height + 2) { this.target.style.marginTop = '-' + this.height + 'px'; } else { this.target.style.marginTop = String(npx) + 'px'; }
            break;
        case 3: 	//right to left
            var opx = this.target.style.marginRight.split("px")[0];
            var pxstep = Math.round((this.width / Math.round(this.step * 0.5)) + 0.5);
            var npx = Number(opx) - Number(pxstep);
            if (Math.abs(npx) > this.width + 2) { this.target.style.marginRight = '-' + this.width + 'px'; } else { this.target.style.marginRight = String(npx) + 'px'; }
            break;
    }
    this.i++	//计数器+1
    if (this.i > (Math.round(this.step * 0.5) - 1)) { window.clearInterval(this.intervalid); this.i = 0; this.status = 0; this.target.style.display = "none"; } //循环完毕，清除循环定时
}