How to return data to the front desk in php

How PHP returns data to the front desk:

1. PHP connects to the database to obtain the database information and puts it into json_encode($css);{The file is: db.php }

Using the json_encode() built-in function in php (php > 5.2) can enable data in php to be transferred and used well with other languages.

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();

2. Put the data of json_encode($css) in success: function(data), as follows: {baixing.html}

$.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[i][3]+'
'+
                        '
'+
                        '￥'+result[i][4]+''+
                        '￥'+result[i][5]+''+
                        ' 预定：'+result[i][6]+'件'
                '