// JavaScript Document
/**//**
* js分页类
* @param iAbsolute 每页显示记录数
* @param sTableId 分页表格属性ID值，为String
* @param sTBodyId 分页表格TBODY的属性ID值,为String,此项为要分页的主体内容
* @param sDivId 页码显示Div属性ID值，为String
* @Version 1.0.1
* @extensior 葛云杰
* var __variable__; private
* function __method__(){};private

*****     example    *****
*
*
*    <script type="text/javascript">
*    window.onload = function(){page = new Page(4,'albumsongs','group_one','pagelist'); }
* </script>
*
*
**************************
*/
var iAbsolute=20;
function Page(iAbsolute,sTableId,sTBodyId,sDivId){
this.absolute = iAbsolute; //每页最大记录数
this.tableId = sTableId;
this.tBodyId = sTBodyId;
this.DivId = sDivId;
this.rowCount = 0;//记录数
this.pageCount = 0;//页数
this.pageIndex = 0;//页索引
this.__oTable__ = null;//表格引用
this.__oTBody__ = null;//要分页内容
this.__dataRows__ = 0;//记录行引用
this.__oldTBody__ = null;
this.__init__(); //初始化;
};

/*初始化*/
Page.prototype.__init__ = function(){
this.__oTable__ = document.getElementById(this.tableId);//获取table引用
this.__oTBody__ = this.__oTable__.tBodies[this.tBodyId];//获取tBody引用
this.__dataRows__ = this.__oTBody__.rows;
this.rowCount = this.__dataRows__.length;
try{
this.absolute = (this.absolute <= 0) || (this.absolute>this.rowCount) ? this.rowCount : this.absolute; 
this.pageCount = parseInt(this.rowCount%this.absolute == 0 
? this.rowCount/this.absolute : this.rowCount/this.absolute+1);
}catch(exception){}

this.__updateTableRows__();
this.aimPage(0);
};


/*下一页*/
Page.prototype.nextPage = function(){
if(this.pageIndex + 1 < this.pageCount){
   this.pageIndex += 1;
   this.__updateTableRows__();
   this.__displayPageList__(this.pageIndex);
}
};


/*上一页*/
Page.prototype.prePage = function(){
if(this.pageIndex >= 1){
   this.pageIndex -= 1;
   this.__updateTableRows__();
   this.__displayPageList__(this.pageIndex);
}
};


/*首页*/
Page.prototype.firstPage = function(){
if(this.pageIndex != 0){
   this.pageIndex = 0;
   this.__updateTableRows__();
   this.__displayPageList__(this.pageIndex);
} 
};


/*尾页*/
Page.prototype.lastPage = function(){
if(this.pageIndex+1 != this.pageCount){
   this.pageIndex = this.pageCount - 1;
   this.__updateTableRows__();
   this.__displayPageList__(this.pageIndex);
}
};

/*页定位方法*/
Page.prototype.aimPage = function(iPageIndex){
if(iPageIndex > this.pageCount-1){
   this.pageIndex = this.pageCount - 1; }
  
else if(iPageIndex < 0){
   this.pageIndex = 0;}
  
else{
   this.pageIndex = iPageIndex;}  
this.__updateTableRows__();
this.__displayPageList__(iPageIndex);
};

/*页码从0开始*/
Page.prototype.__displayPageList__ = function(iPageIndex){
var strResult = "";
//显示上一页
if(this.pageIndex > 0){
   strResult += '<a href="javascript:void(0);" onclick="page.prePage();">上一页</a>';
}else{
   strResult += '上一页';
}
var startIndex = (iPageIndex - 10) >= 0 ? ( iPageIndex - 10) :0;
var endIndex = (iPageIndex + 10) <= (this.pageCount -1) ? (iPageIndex + 10) : (this.pageCount -1);

if(this.pageCount > 1){  
   for(var i = startIndex; i <= endIndex; i++){ 
    if(i == iPageIndex){
     strResult += '&nbsp;&nbsp;[' + (i + 1)+ ']';
     }
    else{
     strResult += '&nbsp;&nbsp;<a href="javascript:void(0);" onclick="page.aimPage('+ i +')">' + (i + 1)+ '</a>';}
    } 
}

//显示下一页
if(this.pageIndex < this.pageCount -1){
   strResult += '&nbsp;&nbsp;<a href="javascript:void(0);" onclick="page.nextPage();">下一页</a>';
}else{
   strResult += '&nbsp;&nbsp;下一页';
}
if(isNaN(this.pageCount)){
	this.pageCount=0;
}
strResult+="&nbsp;&nbsp;&nbsp;&nbsp;第" +(this.pageIndex+1)+"页&nbsp;&nbsp;&nbsp;&nbsp;共"+this.pageCount+"页";
//显示分页页码
this.__$$$__(this.DivId).innerHTML = strResult;
}

/*为了兼容firfox , opera和IE*/
Page.prototype.__$$$__ =function ($){ 
if (document.getElementById){
   return document.getElementById($);}
else if (document.all){
   return document.all[$];}
else if (document.layers){
   return document.layers[$];}
else {return null;}
}


/*执行分页时，更新显示表格内容*/
Page.prototype.__updateTableRows__ = function(){
var iCurrentRowCount = this.absolute * this.pageIndex;
var iMoreRow = this.absolute+iCurrentRowCount > this.rowCount ? this.absolute+iCurrentRowCount - this.rowCount : 0;
var tempRows = this.__cloneRows__();
//alert(tempRows === this.dataRows);
//alert(this.dataRows.length);
var removedTBody = this.__oTable__.removeChild(this.__oTBody__);
var newTBody = document.createElement("TBODY");
newTBody.setAttribute("id", this.tBodyId);

for(var i=iCurrentRowCount; i < this.absolute+iCurrentRowCount-iMoreRow; i++){
   newTBody.appendChild(tempRows[i]);}
  
this.__oTable__.appendChild(newTBody);
/**//*
this.dataRows为this.oTBody的一个引用，
移除this.oTBody那么this.dataRows引用将销失,
code:this.dataRows = tempRows;恢复原始操作行集合.
*/
this.__dataRows__ = tempRows;
this.__oTBody__ = newTBody;
//alert(this.dataRows.length);
//alert(this.absolute+iCurrentRowCount);
//alert("tempRows:"+tempRows.length);

};


/*克隆原始操作行集合*/
Page.prototype.__cloneRows__ = function(){
var tempRows = [];
for(var i=0; i<this.__dataRows__.length; i++){
/**//*
code:this.dataRows[i].cloneNode(param), 
param = 1 or true:复制以指定节点发展出去的所有节点,
param = 0 or false:只有指定的节点和它的属性被复制.
*/
   tempRows[i] = this.__dataRows__[i].cloneNode(1);}
return tempRows;
};