瀑布流检测滚动条拖到底部

```javascript
//瀑布流代码start========================================================================================================
    var start=3;//初始开始偏移量为3(跟据后台代码起初limit而设定)
    var loading=1;//是否进行ajax数据加载
    $(window).scroll(function(){
        //滚动条是否到底部
        var isScrollGoBottom=$(document).scrollTop() > $(document).height()-$(window).height()-$('.footer').height()?1:0;
        if(isScrollGoBottom && loading){//页面拖到底部了
            loading=0;//加载开关设为0
            jsondata={start:start};
            var ajaxurl=classurl+'/index/c/'+'<{$smarty.get.c}>';
            $.get(ajaxurl,jsondata,function(data){
                var redata=eval('('+data+')');
                if(redata.length==0){
                    $('#artlist').append('<div style="width:100%;height:30px;align:center;background:#DDD;text-align:center;line-height:30px;color:#666">已经到底部</div>');
                    loading=0;//加载开关设为0
                }else{
                    $(redata).each(function(i) {//第一级循环
                        var val = redata[i];
                        //==================================================================================================
                        var loadstr="<div class='news_list'>" +
                                    "<div class='n_l_l'>" +
                                        "<img src='"+val.head+"' />" +
                                    "</div>" +
                                    "<div class='n_l_r'>" +
                                        "<ul id='ul"+val.id+"'>" +
                                            "<li>" +
                                            "<span  style='color:#53A3D8; font-weight:bold;'>"+val.name+"</span> " +
                                            "<span style ='color:#53a3d8;'>"+val.posttime+"</span> " +
                                            "<span>发表了新鲜事</span>" +
                                            "</li>" +
                                            "<li>" +
                                            val.content +
                                            "</li>" +
                                            "<li style=' height:30px; line-height:30px;text-align: right'>" ;

if(val.delbool){
                                                loadstr+="<span style=' cursor:pointer; color:#0990d8;' class='delart' data-artid='"+val.id+"' >删除</span>" +" ";
                                            }
                                        loadstr+="<span style='cursor:pointer; color:#0990d8;' class='re' data-artid='"+val.id+"' >回复</span>" +
                                            "</li>" ;
                                        $(val.commentlist).each(function(j){//第二级循环
                                            var comval=val.commentlist[j];
                                            loadstr+="<li style='overflow:hidden; clear:both;border-bottom:1px dotted #999;margin-bottom:5px'>" +
                                                    "<div style='float:left ; width:50px;'><img name='' src='"+comval.head+"' width='32' height='32' alt='' /></div>"
                                                    +
                                                    "<span  style='color:#53A3D8; font-weight:bold;'>"+comval.name.name+"</span>" +
                                                    "<span>"+comval.time+"</span>" +
                                                    "<div style='width:440px; float:right'>"+comval.comment+"<div style=' text-align:right;'>" ;

if(comval.delbool==1){
                                                    loadstr+="<span style='cursor:pointer; color:#0990d8;'   class='de' data-artid='"+val.id+"' >删除</span>" +" " ;
                                                    }
                                                    loadstr+="<span style='cursor:pointer; color:#0990d8;'   class='re' data-artid='"+val.id+"'  data-uname='"+comval.name.name+"'>回复</span>" +
                                                    "</div>" +
                                                    "</div>" +
                                                    "</li>" ;
                                        });
                                        loadstr+="</ul>" +
                                    "</div>" +
                                "</div>";
                        //==================================================================================================
                        $('#artlist').append(loadstr);
                    });
                    loading=1;//加载开关设为1
                    start=start+3;//更改偏移量
                }
            });
        }
    });
    //瀑布流代码end========================================================================================================

```