上拉加载（方式一）

$(window).scroll(function () { //执行监视滚动条事件

    if ($(window).scrollTop() >=$(document).height() - $(window).height()) { //判断滚动是否到达底部
        $("#ajaxlogin").show();
      var num = $("#num").attr("num");//获取当前数量
      var num1 = parseInt(num)+6;//获取获取当页最高数
      $("#num").attr("num",num1)//把最高数赋值给#num
          $.post("{PURL('video/videoajax')}",{ "num":num},function(data){
                      var data=eval(data);
                    //console.log(data)
                    if (data=="") {
                      $("#ajaxlogin").html("已经加载完了");
                    }else{
                         $("#ajaxlogin").hide();
                            setTimeout(function(){
                              $("#ajaxlogin").hide();
                            $.each( data, function( key, value ) {
                                 var mm='<li class="w-video-li"><a href="javascript:;">{if $v.mktp}<img src="{$t_url}images/sp5.jpg" class="w-video-img">{else}<img src="'+data[key]['mktp']+'" class="w-video-img">{/if}<p class="w-pro-title">'+data[key]['name']+'</p><div class="w-detail-mask js-click-video" onclick="videoPLay(this);"  data-url="'+data[key]['video']+'"></div></a></li>';
                                $(mm).appendTo('#num ul');
                            });  
                        },1000);
                    }
          })
   
    } 
});

    <div class="w-video-wrap clearfix container" id="num" num="6">
        <ul class="w-video-ul">
            {foreach $video as $v}
            <li class="w-video-li">
                <a href="javascript:;" title="{$v.name}">
                    {if !$v.mktp}
                    <img src="{$t_url}images/sp5.jpg" alt="{$v.name}" class="w-video-img">
                    {else}
                    <img src="{$v.mktp}" alt="{$v.name}" class="w-video-img">
                    {/if}
                    <p class="w-pro-title">
                        {$v.name}
                    </p>
                    <div class="w-detail-mask"  onclick="videoPLay(this);" data-url="{$v.video}" data-title="{$v.name}" data-date="2016-10-27" data-author="梵天">
                    </div>
                </a>
            </li>
            {/foreach}
        </ul>
    </div>


<div id="ajaxlogin" class="line-scale" style="display: none;">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
</div>

public function videoajax(){
        $num = $_POST['num'];

    
         $video = $this->db->getAll("SELECT * FROM " . TABLE_PREFIX . "video ORDER BY sort DESC LIMIT $num, 6");
        
        echo json_encode($video);
    }