javascript 简单抽屉效果的实现代码_javascript技巧

 

slider.names = new Array();
function slider()
{
this.id = slider.names.length;
slider.names[this.id] = this;
this.target = document.getElementById(arguments[0].parentElement.parentElement.children[0].id); //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 (nopaswitch(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
}