PHP+Mysql+Ajax method to implement Taobao customer service Aliwangwang chat function (front page)

<!--中间内容-->
 <p id="zhongjian">
  <p id="kuangjia" style="height: 550px;width: 620px; margin: 0px auto;border: 1px solid gainsboro;background-color: white;">
   <p id="neirong" style="height: 400px;width: 600px;">
    <p style="height: 100px;width: 620px;background-image: url(../img/bj4.jpg);">
  //取店主用户名，显示店主的头像和姓名<br>　　　　　　　　<?php
   $uid = $_SESSION["uid"];  
   $sql = "select * from users where uid=&#39;zhangsan&#39;";
   $arr = $db->query($sql);
   foreach($arr as $v)
   {    
   echo "
   <p style=&#39;height:100px;float:left;width:100px;float:left;&#39;>
    <p style=&#39;border:2px solid grey;height:84px;width:84px;margin:7px auto; border-radius:10px;overflow:hidden&#39;>
    <img src=&#39;{$v[6]}&#39; height=&#39;80px&#39; width=&#39;80px&#39;/>
    </p>
    </p>
    <p style=&#39;height:100px;width:500px;float:left;&#39;>
    <p style=&#39;height:50px;width:500px;text-align:left;line-height:50px&#39;>
     亲爱的店主
    </p>   
     <p style=&#39;height:50px;width:500px;text-align:left;&#39;>个性签名：
     <input type=&#39;text&#39; placeholder=&#39;不读书怎么对得起今天!&#39; style=&#39;width:280px&#39;>        
    </p>
    </p>
    "; 
   }   
   ?>
   </p>
   <p style="height: 300px;width: 620px;overflow: auto;overflow-x:hidden ;"><br>         //获取session里存取的uid;
    <?php
     $uid = $_SESSION["uid"];     
     $sql3 = "select * from users where uid=&#39;{$uid}&#39;";
         $arr3 = $db->query($sql3);<br>　　　　　　　　　　　　　　　　　　　　//从对话表里读取店主张三和李四所有的对话信息，并按对话时间顺序排序
     $sql2="select * from duihua where uid=&#39;{$uid}&#39; or jsid=&#39;{$uid}&#39; order by dhtime";     
     $arr2= $db->query($sql2);
     foreach($arr2 as $n)
     {<br>        //如果是店主，则信息要显示在左侧
     if($n[2]==&#39;zhangsan&#39;)
     {
     echo "<p style=&#39;height:100px;width:600px;&#39;>
     <p style=&#39;height:100px;width:250px;float:left&#39;>
      <p style=&#39;height:20px;width:250px;font-size:13px;padding-left:20px&#39;>
        {$n[6]}</p>
      <p style=&#39;height:80px;width:50px;float:left&#39;>
       <p style=&#39;height:50px;width:50px;margin:0px auto; border-radius:90px;overflow:hidden;&#39;>
        <img src=&#39;{$v[6]}&#39; height=&#39;50px&#39; width=&#39;50px&#39;/>
       </p>
      </p>
      <p style=&#39;min-height:40px;width:200px;float:left;background-color:cornflowerblue; border-bottom-right-radius: 10px;border-top-right-radius: 10px;border-top-left-radius: 40px;border-bottom-left-radius: 40px;&#39;>
       <p style=&#39;padding-left:20px; line-height:40px&#39;>
        {$n[4]}</p>        
      </p>     
     </p></p>";
     } <br>//如果是李四，则显示在右侧    
     if($n[2]==$uid)
     {            
     echo "<p style=&#39;height:100px;width:600px;margin-right:20px&#39;>
     <p style=&#39;height:100px;width:250px; float:right&#39;>
      <p style=&#39;height:20px;width:250px;font-size:13px;padding-right:20px&#39;>
        {$n[6]}</p>
      <p style=&#39;height:80px;width:50px;float:right&#39;>
       <p style=&#39;height:50px;width:50px;margin:0px auto; border-radius:90px;overflow:hidden;&#39;>
        <img src=&#39;{$arr3[0][6]}&#39; height=&#39;50px&#39; width=&#39;50px&#39;/>
       </p>
      </p>
      <p style=&#39;min-height:40px;width:200px;float:right;background-color:pink; border-bottom-left-radius: 10px;border-top-left-radius: 10px;border-top-right-radius: 40px;border-bottom-right-radius: 40px;&#39;>
       <p style=&#39;padding-left:20px; line-height:40px&#39;>
        {$n[4]}</p>        
      </p>     
     </p></p>"; 
     }          
     }  
     ?>   
   </p>  
   </p> <!--id="neirong"--><br>
  <form role="form">
   <p class="form-group">
   <textarea class="form-control" rows="3" id="words"></textarea> //输入发送内容
   </p>
  </form>
  <p id="fs" style="height: 50px; width: 600px;text-align: right; padding-right: 50px;">
  <button type="button" class="btn btn-success fasong">发送</button>  //点击按钮发送
  </p>
  </p>   
  </p> <!--id=zhongjian--> 　　

<script>
 $(".tc").click(function(){
  $("#kuangjia").show();  
 })
  $(".fasong").click(function(){
  var nr=$("#words").val();
  $.ajax({
   url:"qt-speak-cl.php",
   data:{words:nr},
   type:"POST",
   dataType:"TEXT",
   success: function(data){
    if(data==1)
    {
    window.location.href="qt-dh.php" rel="external nofollow" rel="external nofollow" ; 
    }
    else{
     alert("发送内容不能为空！");
    }
    }
  })
 }) 
  $("#dh").click(function(){
  $.ajax({
   url:"qt-yidu-cl.php",
   dataType:"TEXT",
   success: function(data){
//    alert(data);     
    window.location.href="qt-dh.php" rel="external nofollow" rel="external nofollow" ;    
   }   
  })
 })
</script>

<?php
session_start();
require "DBDA.class.php";
$db = new DBDA(); 
$uid = $_SESSION["uid"];
$words =$_POST["words"];
$chtime=date("Y-m-d H:i:s",time());
$jieshou = "zhangsan";
if(!empty($words))
{
$sql="insert into duihua values (&#39;&#39;,&#39;{$jieshou}&#39;,&#39;{$uid}&#39;,&#39;&#39;,&#39;{$words}&#39;,0,&#39;{$chtime}&#39;)";
echo $db->query($sql,0);
<em id="__mceDel">}
else
{ 
 echo "发送内容不能为空！";
}
?>
</em>