// JavaScript Document


/*
使用方法
调用效果: Effect(1)
其中1为: 被改变对象的id
注意给对象ID的时候一定不要重复
*/
function $G(Read_Id) { return document.getElementById(Read_Id) }
var openedObjId=null
function Effect(ObjectId){
 if (openedObjId){
  $G(openedObjId+"tab").innerHTML = "<a href=#>+</a>";
  Start(openedObjId,'Close');
 }
 if(openedObjId!=ObjectId){
  $G(ObjectId+"tab").innerHTML = "<a href=#>-</a>";
  Start(ObjectId,'Opens');
  openedObjId=ObjectId
 }
 else openedObjId=null
}
function Start(ObjId,method){
var BoxHeight = $G(ObjId).offsetHeight;      //获取对象高度
var MinHeight = 5;         //定义对象最小高度
var MaxHeight = 400;         //定义对象最大高度
var BoxAddMax = 1;         //递增量初始值
var Every_Add = 1;        //每次的递(减)增量[数值越大速度越快]
var Reduce    = (BoxAddMax - Every_Add);
var Add       = (BoxAddMax + Every_Add);
//关闭动作**************************************
if (method == "Close"){
var Alter_Close = function(){      //构建一个虚拟的[递减]循环
 BoxAddMax /= Reduce;
 BoxHeight -= BoxAddMax;
 if (BoxHeight <= MinHeight){
  $G(ObjId).style.display = "none";
  window.clearInterval(BoxAction);
 }
 else $G(ObjId).style.height = BoxHeight;
}
var BoxAction = window.setInterval(Alter_Close,1);
}
//打开动作**************************************
else if (method == "Opens"){
var Alter_Opens = function(){
 BoxAddMax *= Add;
 BoxHeight += BoxAddMax;
 if (BoxHeight >= MaxHeight){
  $G(ObjId).style.height = MaxHeight;
  window.clearInterval(BoxAction);
 }else{
 $G(ObjId).style.display= "block";
 $G(ObjId).style.height = BoxHeight;
 }
}
var BoxAction = window.setInterval(Alter_Opens,1);
}
}