js动态生成页码，只显示五个页码

html代码：

<div id="pageNumberDiv">
	<ul class="pagination">ul>
div>

js代码：

function initPage(pageInfo){
	//清除掉之前的页码
	$(".pagination li").remove();
	
	var total = pageInfo.allPageNum;//总页数
	var pageNum = pageInfo.curPageNum;//当前页
	var firstPage = 1;//第一页
	var prePage = pageNum - 1;//上一页
	var nextPage = pageNum + 1;//下一页
	var lastPage = total;
    
    // 先拼接点击事件   ，用于解决字符串拼接的问题 
	var firstPageStr = "retrieve(1)";
	var prePageStr = "retrieve("+prePage+")";
	var nextPageStr = "retrieve("+nextPage+")";
	var lastPageStr = "retrieve("+lastPage+")";
	
	
    //做判断，满足某些条件时，不能点击
	if(firstPage==pageNum){
		$(".pagination").append("
首页
");
	}else{
		$(".pagination").append("
+firstPageStr+">首页
");
	}
	if(prePage<=0){
		$(".pagination").append("
上一页
");
	}else{
		$(".pagination").append("
+prePageStr+">上一页
");
	}
	
	//生成中间的页面
	if(pageNum<=3){
		for(var i=1; i<=(total<=5?total:5); i++){
			if(i==pageNum){
				$(".pagination").append("
"+i+"
");
			}else{
				var pageNumber = "retrieve("+i+")";
				$(".pagination").append("
+pageNumber+">"+ i+ "
");
			}
		}
	}else if(pageNum>3 && total<=(pageNum+2)){
		for(var i=total-4; i<=total; i++){
			if(i==pageNum){
				$(".pagination").append("
"+i+"
");
			}else{
				var pageNumber = "retrieve("+i+")";
				$(".pagination").append("
+pageNumber+">"+ i+ "
");
			}
		}
	}else if(pageNum>3 && total>(pageNum+2)){
		for(var i=pageNum-2; i<=pageNum+2; i++){
			if(i==pageNum){
				$(".pagination").append("
"+i+"
");
			}else{
				var pageNumber = "retrieve("+i+")";
				$(".pagination").append("
+pageNumber+">"+ i+ "
");
			}
		}
	}
	
	if(nextPage<=0 || nextPage > total){
		$(".pagination").append("
下一页
");
	}else{
		$(".pagination").append("
+nextPageStr+">下一页
");
	}
	if(lastPage==pageNum){
		$(".pagination").append("
尾页
");
	}else{
		$(".pagination").append("
+lastPageStr+">尾页
");
	}
}