php从数据库中获取数据用ajax传送到前台的方法

<span style="font-size:14px;"><?php
$host="localhost";
$username="root";
$password="root";
$dbName="baixing";
$port=3306;
$conn=new mysqli($host,$username,$password,$dbName,$port);
if(!$conn){
 die("error:".$conn->connect_error);
}
//设置查询结果的编码，一定要放在query之前
$conn->query("SET NAMES 'UTF8'");
$result=$conn->query("select * from hotgoods");
//$conn->query()获取的是二进制
//将查询的结果集封装到一个数组里
$css=$result->fetch_all();
//以json的格式发送ajax的success中由data接收
echo json_encode($css);
$conn->close();</span>

$.ajax({
  type: 'POST',
  url: 'db.php',
  data:{
//   "username":"admin",
//   "password":"123456"
  },
  success: function (data) {
   var result=eval("("+data+")");
   alert(result);
   for(var i=0;i<result.length;i++){
    var str='<div class="home1">'+
      '<img src="'+result[i][1]+'" alt="'+result[i][3]+'"/>'+
      '<p><a href="'+result[i][2]+'" rel="external nofollow" rel="external nofollow" >'+result[i][3]+'</a></p>'+
      '<div class="price">'+
      '<span>￥'+result[i][4]+'</span>'+
      '<del>￥'+result[i][5]+'</del>'+
      ' <a href="#" rel="external nofollow" rel="external nofollow" >预定：<b>'+result[i][6]+'</b>件</a>'
    '</div> </div>'
    $(".box7 #hotSale").append(str);//追加到你需要放在的位置
   }
  }
 });$.ajax({
  type: 'POST',
  url: 'db.php',
  data:{
//   "username":"admin",
//   "password":"123456"
  },
  success: function (data) {
   var result=eval("("+data+")");
   alert(result);
   for(var i=0;i<result.length;i++){
    var str='<div class="home1">'+
      '<img src="'+result[i][1]+'" alt="'+result[i][3]+'"/>'+
      '<p><a href="'+result[i][2]+'" rel="external nofollow" rel="external nofollow" >'+result[i][3]+'</a></p>'+
      '<div class="price">'+
      '<span>￥'+result[i][4]+'</span>'+
      '<del>￥'+result[i][5]+'</del>'+
      ' <a href="#" rel="external nofollow" rel="external nofollow" >预定：<b>'+result[i][6]+'</b>件</a>'
    '</div> </div>'
    $(".box7 #hotSale").append(str);
   }
  }
 });