var pageNav = pageNav || {};
 pageNav.fn = null;
 //p为当前页码,pn为总页数
 pageNav.nav = function(p, pn) {
	 //只有一页,直接显示1   
	 if (pn <= 1) {
		 this.p = 1;
		 this.pn = 1;
		 return this.pHtml2(1);
	 }
	 if (pn < p) {
		p = pn;   
	 };
	 var re = "";
	 //第一页   
	 if (p <= 1) {
		p = 1;   
	 } else {
	 //非第一页
	 re += this.pHtml(p - 1, pn, "上一页");
	 //总是显示第一页页码
	 re += this.pHtml(1, pn, "1");   }
	 //校正页码
	 this.p = p;
	 this.pn = pn; 
	 //开始页码
	 var start = 2;
	 var end = (pn < 9) ? pn: 9;
	 //是否显示前置省略号,即大于10的开始页码
	 if (p >= 7) {
	 re += "...";
	 start = p - 4;
	 var e = p + 4;
		end = (pn < e) ? pn: e;
	 } 
	 for (var i = start; i < p; i++) {
		re += this.pHtml(i, pn);
	 };
	 re += this.pHtml2(p);
	 for (var i = p + 1; i <= end; i++) {
		re += this.pHtml(i, pn);   
	 }; 
	 if (end < pn) {
		 re += "<span>...<span>";
		 //显示最后一页页码,如不需要则去掉下面这一句
		 re += this.pHtml(pn, pn);   
	 };
	 if (p < pn) {
		re += this.pHtml(p + 1, pn, "下一页");
	 };
	  re += "<a>当前第"+p+"页</a>";
	  
	 return re;
 }; 
 //显示非当前页
 pageNav.pHtml = function(pageNo, pn, showPageNo) {
	 showPageNo = showPageNo || pageNo;
	 var H = " <a href='javascript:pageNav.go(" + pageNo + "," + pn + ");' data-currpage='" + pageNo + "'>" + showPageNo + "</a> "; 
	 return H;
 };
 //显示当前页
 pageNav.pHtml2 = function(pageNo) {
	 var H = " <a class='current'>" + pageNo + "</a>";
	 return H; 
 };
 //输出页码,可根据需要重写此方法
 pageNav.go = function(p, pn) {
	 //$("#pageNav").html(this.nav(p,pn));//如果使用jQuery可用此句 
	 document.getElementById("pagelist").innerHTML = this.nav(p, pn);
	 if (this.fn != null) {
		this.fn(this.p, this.pn);
	 };
 };