面向对象版js分页

基于前一个js分页，我将代码改成一个面向对象版的js分页，代码如下
http://peng666.github.io/blogs/pageobj
<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<style type="text/css">

a{

    margin: 5px;

}

</style>

<title>分页</title>

<script type="text/javascript">

window.onload=function(){

    new page(

        {id:'div1',

        nowNum:8,

        allNum:10,

        callback:function(now,all){

            alert('当前页：'+now+','+'总共'+all+'页')

        }

        }

    )

}

function page(json){

    this.json=json;

    if(!this.json.id){

        return false

    }

    this.obj=null;

    this.nowNum=null;

    this.allNum=null;

    this.callback=null;

    var _this=this;

    this.obj=document.getElementById(this.json.id);

    this.nowNum=this.json.nowNum||1;

    this.allNum=this.json.allNum||5;

    this.callback=this.json.callback||function(){};

    if(this.nowNum >3 && this.allNum >5){

        var oA=null;

        this.oA=document.createElement('a');

        this.oA.href="#"+1;

        this.oA.innerHTML="首页";

        this.obj.appendChild(this.oA)

    }

    if(this.nowNum>1){

        var oA=null;

        this.oA=document.createElement('a');

        this.oA.href="#"+(this.nowNum-1);

        this.oA.innerHTML="上一页";

        this.obj.appendChild(this.oA)

    }

    if(this.allNum<=5){

        for(var i=0;i<this.allNum;i++){

            var oA=null;

            this.oA=document.createElement('a');

            this.oA.href='#'+(i+1);

            if(this.nowNum==i){

                this.oA.innerHTML=(i+1);

            }else{

                this.oA.innerHTML='['+ (i+1) +']';

            }

            this.obj.appendChild(this.oA);

        }

    }else{

        for(var i=1;i<=5;i++){

            var oA=null;

            this.oA=document.createElement('a');

            if(this.nowNum==1||this.nowNum==2){

                this.oA.href='#'+i;

                this.oA.innerHTML='['+i+']';

                if(this.nowNum==i){

                    this.oA.innerHTML=i

                }

            }else if((this.allNum - this.nowNum) == 0||(this.allNum - this.nowNum == 1)){

                this.oA.href='#'+(this.allNum-5+i);

                if(this.allNum - this.nowNum==0 && i==5){

                    this.oA.innerHTML=(this.allNum-5+i);

                }else if(this.allNum - this.nowNum==1 && i==4){

                    this.oA.innerHTML=(this.allNum-5+i);

                }else{

                    this.oA.innerHTML='['+(this.allNum-5+i)+']';

                }

            }else{

                this.oA.href = '#' + (this.nowNum - 3 + i);

                if(i==3){

                    this.oA.innerHTML=(this.nowNum-3+i);

                }else{

                    this.oA.innerHTML='['+(this.nowNum-3+i)+']';

                }

            }

            this.obj.appendChild(this.oA);

        }

    }

    if((this.allNum - this.nowNum) > 0){

        var oA=null;

        this.oA=document.createElement('a');

        this.oA.href='#'+(this.nowNum+1);

        this.oA.innerHTML = '下一页';

        this.obj.appendChild(this.oA);

    }

    if((this.allNum - this.nowNum)>2){

        var oA=null;

        this.oA=document.createElement('a');

        this.oA.href='#'+this.allNum;

        this.oA.innerHTML = '尾页'

        this.obj.appendChild(this.oA);

    }

    this.callback(this.nowNum,this.allNum);

    var aA=null;

    this.aA=this.obj.getElementsByTagName('a');

    for(var i=0;i<this.aA.length;i++){

        var _this=this;

        this.aA[i].onclick=function(){

            _this.change(this);

        };

    }

}

page.prototype.change=function(btn){

            var nowNum=null;

            this.nowNum = parseInt(btn.getAttribute('href').substring(1));

            this.obj.innerHTML='';

            new page(

                {

                    id:    this.json.id,

                    nowNum:this.nowNum,

                    allNum:this.allNum

                }

            )

}

</script>

</head>

<body>

<div id="div1">

    <!-- <a href="#1">1</a>

    <a href="#1">2</a>

    <a href="#1">3</a>

    <a href="#1">4</a>

    <a href="#1">5</a> -->

</div>

</body>

</html>