javascript - 使用本地 AJAX 请求解析 JSON 数据

Question

我在网络服务器上有一个 php 文件，它对 MySQL 数据库执行查询。

我正在我的电脑(本地)上测试一个网站，该网站使用带有 AJAX 请求的 js 文件从该 php 文件获取 JSON 数据。

这样可以吗，还是js文件必须和php文件放在同一个域服务器上？

因为解析数据的 console.log 给了我这个错误:

Uncaught SyntaxError: Unexpected token I

这是ajax调用

$.ajax({
    method:"POST", 
    crossDomain:true, 
    url:"url for the php file",
    data:{
        query: "SELECT * FROM course_categories;"
    },

    success: function(response){

        var course_categories=JSON.parse(response); 
        console.log(course_categories);
        var el="";
        console.log(course_categories.length);
        for(var i=0;i<(course_categories.length);i++)
        {

        }

    },

    error: function(request,error){
        console.log("ERROR: Request " + request + "\nSpecific Error: " + error);
    }

虽然这是 PHP 调用

<?php

//get all the courses from the database and reply using the JSON structure

//$mysqli=new msqli("localhost","username","password","dbname");

 $mysqli=new mysqli("localhost","hey","","db_name");


if(mysqli_connect_errno()) //returns a number of the error if there is any,              if not
{
echo json_encode("Error to connect to DBMS".mysqli_connect_error());

exit(); //closes the connection
}
else
{


$query=$_POST["query"];
    //$query="SELECT * FROM course_categories";
       $result=$mysqli->query($query); //do a query (->query) setted by $query, using the $mysqli variable, and store the data in $result 

if($result->num_rows >0) //if there is at least one row...
{
    $myArray= array(); //...create an array...
    while($row = $result->fetch_array(MYSQL_ASSOC))
    { 
        //...and fetch it. Everytime this operation returns a row,
        $myArray[]=$row; //...and added to myArray ([] means autoincrement).
    }

}

echo json_encode(utf8ize($myArray));

 //free result
$result->close();

//close connection
$mysqli->close(); 

}

Answer 1

我做到了。我所要做的就是删除 crossDomain:true 行，以便 JSON 能够真正解析数据。