使用Javascript从PHP获取JSON数据：

Question

In my javascript I'm getting this error:

Uncaught SyntaxError: Unexpected token P in JSON at position 0, at JSON.parse (), at XMLHttpRequest.req.onreadystatechange

when trying to receive some stuff from a PHP script. I've seen some similar questions but I couldn't find a solution for my case.

My server PHP code:

<?php
header('Content-Type: application/json');
$myObj->name = "John";
$myObj->age = 30;
$myObj->city = "New York";
$myJSON = json_encode($myObj,JSON_UNESCAPED_UNICODE);
echo $myJSON;
?>

My client javascript:

var req = new XMLHttpRequest();
req.onreadystatechange = function () {
    if (this.readyState == XMLHttpRequest.DONE && this.status == 200) {
        var s = req.responseText;
        var users = JSON.parse(s);
        console.table(s);
    } 
}
req.open("GET", "./get_info.php", true);

When I run the PHP file using the browser I get this:

{"name":"John","age":30,"city":"New York"}

which I believe is correct.

Any suggestion?

Answer 1

Your code is working fine , you could check if you are getting any warning in php response which cause an error in JSON.parse at client side, meanwhile same error I got while running your script in my system. Getting Response from php -

<br />
<b>Warning</b>:  Creating default object from empty value in <b>/opt/lampp/htdocs/tst/get_info.php</b> on line <b>5</b><br />
{"name":"John","age":30,"city":"New York"}

At Client Side :

Uncaught SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at XMLHttpRequest.req.onreadystatechange 

Fixed this issue by disabling the warning in my php code -

error_reporting(E_ERROR | E_PARSE);