原生javascript实现的分页插件pagenav

/*
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author:Keel ([e-mail])
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页码显示jquery插件,只需要存在#pageNav,则会在其中显示页码.
调用时可根据需要先重写go方法.(已去除jquery依赖)

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示例(注意：页面中放置id为pageNav的html对象):

//转到页码时触发的自定义方法,p为当前页码,pn为总页数
pageNav.fn = function(p,pn){
alert(p+","+pn);
};
//初始跳到第3页,共33页
pageNav.go(3,33);

 */
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 += "...";
		//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");
	};
	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 + ");' class='pageNum'>" + showPageNo + "</a> ";
	return H;

};
//显示当前页
pageNav.pHtml2 = function (pageNo) {
	var H = " <span class='cPageNum'>" + pageNo + "</span> ";
	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("pageNav").innerHTML = this.nav(p, pn);
	if (this.fn != null) {
		this.fn(this.p, this.pn);
	};
};

演示地址：http://demo.jb51.net/js/2014/pagenav/