JS+PHP瀑布流效果

miai.php，代码如下：

$link = mysql_connect("localhost","root",""); //连接数据库 

$num = 0 *3;//分页 
if(isset($_POST['num']) && $_POST['num'] != 0)
    $num +1; 
else
    $num = 0;
$sql = "select id,image from liu.miai limit ".$num.",3";//分条 
$result = mysql_query($sql,$link); 

$json_arr = array(); 
while($row = mysql_fetch_array($result)){  
    $json_arr[]  = (object)$row; 
} 
echo json_encode($json_arr);