最近在學(xué)javascript，才慢慢開始讀懂JS代碼。對(duì)HTML前臺(tái)AJAX加載技術(shù)研究了一番，像博客站或者圖片站運(yùn)用AJAX異步無(wú)限加載，做成瀑布流，提高用戶體驗(yàn)，這是AJAX異步加載的優(yōu)點(diǎn)。
AJAX異步加載的弊端：屬于WEB前端技術(shù)，蜘蛛不會(huì)抓JS調(diào)用的內(nèi)容，也就是并不利于SEO優(yōu)化。所以要運(yùn)用這個(gè)功能的話最好有一部分直接調(diào)用，另一部分采用AJAX異步加載。
接下來(lái)用DedeCMS來(lái)做AJAX異步加載WEB前端開發(fā)。網(wǎng)上有諸多教程，經(jīng)過(guò)筆者整理，給出詳細(xì)說(shuō)明，修正后分享給大家。
打開/plus/list.php，找到
require_once(dirname(__FILE__)."/../include/common.inc.php");
下面增加代碼
if(isset($_GET['ajax'])){
$typeid = isset($_GET['typeid']) ? intval($_GET['typeid']): 0;//傳遞過(guò)來(lái)的分類ID
$page = isset($_GET['page']) ? intval($_GET['page']): 0;//頁(yè)碼
$pagesize = isset($_GET['pagesize']) ? intval($_GET['pagesize']): 15;//每頁(yè)多少條，也就是一次加載多少條數(shù)據(jù)
$start = $page>0 ? ($page-1)*$pagesize : 0;//數(shù)據(jù)獲取的起始位置。即limit條件的第一個(gè)參數(shù)。
$typesql = $typeid ? " WHERE typeid=$typeid" : '';//這個(gè)是用于首頁(yè)實(shí)現(xiàn)瀑布流加載，因?yàn)槭醉?yè)加載數(shù)據(jù)是無(wú)需分類的，所以要加以判斷，如果無(wú)需
$total_sql = "SELECT COUNT(id) as num FROM `#分隔符@__archives` $typesql ";
$temp = $dsql->GetOne($total_sql);
$total = 0;//數(shù)據(jù)總數(shù)
$load_num =0;
if(is_array($temp)){
$load_num= round(($temp['num']-15)/$pagesize);//要加載的次數(shù),因?yàn)槟J(rèn)已經(jīng)加載了
$total = $temp['num'];
}
$sql = "SELECT a.*,t.typedir,t.typename,t.isdefault,t.defaultname,t.namerule,
t.namerule2,t.ispart, t.moresite,t.siteurl,t.sitepath
FROM `#分隔符@__archives` as a JOIN `#分隔符@__arctype` AS t ON a.typeid=t.id $typesql ORDER BY id DESC LIMIT $start,$pagesize";
//echo "$sql";
$dsql->SetQuery($sql);
$dsql->Execute('list');
$statu = 0;//是否有數(shù)據(jù)，默認(rèn)沒有數(shù)據(jù)
$data = array();
$index = 0;
while($row = $dsql->GetArray("list")){
$row['info'] = $row['info'] = $row['infos'] = cn_substr($row['description'],160);
$row['id'] = $row['id'];
$row['filename'] = $row['arcurl'] = GetFileUrl($row['id'],
$row['typeid'],$row['senddate'],$row['title'],$row['ismake'],
$row['arcrank'],$row['namerule'],$row['typedir'],$row['money'],
$row['filename'],$row['moresite'],$row['siteurl'],$row['sitepath']);
$row['typeurl'] = GetTypeUrl($row['typeid'],$row['typedir'],
$row['isdefault'],$row['defaultname'],$row['ispart'],
$row['namerule2'],$row['moresite'],$row['siteurl'],$row['sitepath']);
if($row['litpic'] == '-' || $row['litpic'] == ''){
$row['litpic'] = $GLOBALS['cfg_cmspath'].'/images/defaultpic.gif';
}
if(!preg_match("#^http:\/\/#i", $row['litpic']) &&$GLOBALS['cfg_multi_site'] == 'Y'){
$row['litpic'] = $GLOBALS['cfg_mainsite'].$row['litpic'];
}
$row['picname'] = $row['litpic'];//縮略圖
$row['stime'] = GetDateMK($row['pubdate']);
$row['typelink'] = "<a href='".$row['typeurl']."'>".$row['typename']."</a>";//分類鏈
$row['fulltitle'] = $row['title'];//完整的標(biāo)題
$row['shorttitle'] = $row['shorttitle'];//副標(biāo)題
$row['title'] = cn_substr($row['title'], 60);//截取后的標(biāo)題
$data[$index] = $row;
$index++;
}
if(!empty($data)){
$statu = 1;//有數(shù)據(jù)
}
$result =array('statu'=>$statu,'list'=>$data,'total'=>$total,'load_num'=>$load_num);
echo json_encode($result);//返回?cái)?shù)據(jù)
exit();
}
注意上面標(biāo)紅的#分隔符@，使用的時(shí)候務(wù)必刪除“分隔符”三個(gè)字。
模板文件增加內(nèi)容
在需要用AJAX異步加載的模板的</head>前增加代碼
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>
<script type="text/javascript">
var loadConfig = {
url_api:'{dede:global.cfg_cmspath/}/plus/list.php', //修正plus目錄
typeid:{dede:field name='typeid'/}, //首頁(yè)此處是typeid:0,
page:2,
pagesize:3,
loading : 0,
}
function loadMoreApply(){
if(loadConfig.loading == 0){
var typeid = loadConfig.typeid;
var page = loadConfig.page;
var pagesize = loadConfig.pagesize;
var url = loadConfig.url_api,data={ajax:'pullload',typeid:typeid,page:page,pagesize:pagesize};
var sTop = document.body.scrollTop || document.documentElement.scrollTop, dHeight = $(document).height(), cHeight = document.documentElement.clientHeight;
console.log(dHeight);
if (sTop + cHeight >= dHeight - cHeight) {
loadConfig.loading = 1;
function ajax(url, data) {
$.ajax({url: url,data: data,async: false,type: 'GET',dataType: 'json',success: function(data) {
addContent(data);
}});
}
ajax(url,data);
}
}
}
function addContent (rs){
if(rs.statu== 1){
var data = rs.list;
var total = rs.total;
var arr=[];
var length = data.length;
for(var i=0;i<length;i++){
arr.push('<li>');
arr.push('<a href="'+data[i].arcurl+'" class="preview">');
arr.push('<img class="" width="" height="" alt="data[i].title" src="'+data[i].picname+'" />');
arr.push('</a>');
arr.push('[<b>'+data[i].typelink+'</b>]');
arr.push('<a href="'+data[i].arcurl+'" class="title">'+data[i].title+'</a>');
arr.push('</li>');
}
$('.data-list').append(arr.join(''));
loadConfig.load_num = rs.load_num;
if(total<loadConfig.page*loadConfig.pagesize || loadConfig.page > loadConfig.load_num){
window.removeEventListener('srcoll',loadMoreApply,false);
}
loadConfig.page++;
loadConfig.loading = 0;
}
}
function pullLoad(){
window.addEventListener('scroll', loadMoreApply, false);
}
pullLoad();
</script>
首頁(yè)HTML代碼示例
<p class="listbox"> <ul class="e2"> <p class="data-list"> {dede:arclist row='3'} <li> [field:array runphp='yes']@me = (empty(@me['litpic']) ? "" : "<a href='{@me['arcurl']}' class='preview'><img src='{@me['litpic']}'/></a>"); [/field:array] [<b>[field:typelink/]</b>] <a href="[field:arcurl/]" class="title">[field:title/]</a> <span class="info"> <small>日期：</small>[field:pubdate function="GetDateTimeMK(@me)"/] <small>點(diǎn)擊：</small>[field:click/] <small>好評(píng)：</small>[field:scores/] </span> <p class="intro"> [field:description/]... </p> </li> {/dede:arclist} </p><!--data-list--> </ul> </p> <!-- /listbox -->
注意：首頁(yè)模板用arclist標(biāo)簽，用row='3'是初始化調(diào)用的3條；列表模板用list標(biāo)簽，用pagesize='3'。模板里面的<p class="data-list“>與js里面的data-list對(duì)應(yīng)，需要把循環(huán)部分全部包裹起來(lái)。
