PHP+Mysql+Ajax实现淘宝客服或阿里旺旺聊天功能(前台页面)

<!--中间内容-->
 <div id="zhongjian">
  <div id="kuangjia" style="height: 550px;width: 620px; margin: 0px auto;border: 1px solid gainsboro;background-color: white;">
   <div id="neirong" style="height: 400px;width: 600px;">
    <div 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='zhangsan'";
   $arr = $db->query($sql);
   foreach($arr as $v)
   {    
   echo "
   <div style='height:100px;float:left;width:100px;float:left;'>
    <div style='border:2px solid grey;height:84px;width:84px;margin:7px auto; border-radius:10px;overflow:hidden'>
    <img src='{$v[6]}' height='80px' width='80px'/>
    </div>
    </div>
    <div style='height:100px;width:500px;float:left;'>
    <div style='height:50px;width:500px;text-align:left;line-height:50px'>
     亲爱的店主
    </div>   
     <div style='height:50px;width:500px;text-align:left;'>个性签名：
     <input type='text' placeholder='不读书怎么对得起今天!' style='width:280px'>        
    </div>
    </div>
    "; 
   }   
   ?>
   </div>
   <div style="height: 300px;width: 620px;overflow: auto;overflow-x:hidden ;"><br>         //获取session里存取的uid;
    <?php
     $uid = $_SESSION["uid"];     
     $sql3 = "select * from users where uid='{$uid}'";
         $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
     $sql2="select * from duihua where uid='{$uid}' or jsid='{$uid}' 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]=='zhangsan')
     {
     echo "<div style='height:100px;width:600px;'>
     <div style='height:100px;width:250px;float:left'>
      <div style='height:20px;width:250px;font-size:13px;padding-left:20px'>
        {$n[6]}</div>
      <div style='height:80px;width:50px;float:left'>
       <div style='height:50px;width:50px;margin:0px auto; border-radius:90px;overflow:hidden;'>
        <img src='{$v[6]}' height='50px' width='50px'/>
       </div>
      </div>
      <div style='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;'>
       <p style='padding-left:20px; line-height:40px'>
        {$n[4]}</p>        
      </div>     
     </div></div>";
     } <br>//如果是李四，则显示在右侧    
     if($n[2]==$uid)
     {            
     echo "<div style='height:100px;width:600px;margin-right:20px'>
     <div style='height:100px;width:250px; float:right'>
      <div style='height:20px;width:250px;font-size:13px;padding-right:20px'>
        {$n[6]}</div>
      <div style='height:80px;width:50px;float:right'>
       <div style='height:50px;width:50px;margin:0px auto; border-radius:90px;overflow:hidden;'>
        <img src='{$arr3[0][6]}' height='50px' width='50px'/>
       </div>
      </div>
      <div style='min-height:40px;width:200px;float:right;background-color:pink; border-bottom-left-radius: 10px;border-top-left-radius: 10px;border-top-right-radius: 40px;border-bottom-right-radius: 40px;'>
       <p style='padding-left:20px; line-height:40px'>
        {$n[4]}</p>        
      </div>     
     </div></div>"; 
     }          
     }  
     ?>   
   </div>  
   </div> <!--id="neirong"--><br>
  <form role="form">
   <div class="form-group">
   <textarea class="form-control" rows="3" id="words"></textarea> //输入发送内容
   </div>
  </form>
  <div 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
  </div>
  </div>   
  </div> <!--id=zhongjian-->