从 PHP 获取数据的 JavaScript 问题

Question

I'm new to PHP, and i'm trying to fetch data from PHP to JavaScript. When i do that, JavaScript always giving me the same error "Unexpected token < in JSON at position 0". I don't have any idea what to do. I'm stuck...Help Help ! x)

There is the code

JavaScript

 var xmlhttp = new XMLHttpRequest();

 xmlhttp.onreadystatechange = function () {
 if (this.readyState == 4 && this.status == 200) {
    var myObj = JSON.parse(this.responseText);
    document.getElementById("demo").innerHTML = myObj.name;
  }
 };

xmlhttp.open("GET", "data.php", true);
xmlhttp.send();

PHP

<?php
  $myObj->name = "John";
  $myObj->age = 30;
  $myObj->city = "New York";

  $myJSON = json_encode($myObj);

  echo $myJSON;

?>

Answer 1

I think you are getting an issue of object
Object $myObj need to be initialized before using it
I have updated the code (Initialized the object) please use the below code on php page to resolve the issue

<?PHP
  $myObj = new StdClass();
  $myObj->name = "John";
  $myObj->age = 30;
  $myObj->city = "New York";

  $myJSON = json_encode($myObj);

  echo $myJSON; 

Answer 2

Obviously, the response returned for your XMLHttpRequest is not a valid JSON . Provided that your PHP codesample is complete, PHP will most likely(*) echo an E_WARNING error before outputting the JSON string, although your code will work. Related question and solution here . Easiest way to check is to view the raw response in your browser's dev tools (supported by all major browsers). If the response contains anything except the JSON string, JSON.parse() will throw an error.

(*)This depends on your error reporting settings