Why ajax response doesn't work?

Question

I have a .php script like this:

$arr   =  array();
$arg1  =  $_GET['arg1'];
$arg2  =  $_GET['arg2'];

if ($arg1 !==1 && $arg2 !==0) {
  $arr['msg'] = 'wrong values!';
  header('Content-Type: application/json');     
  echo json_encode($arr);
  exit();
}

$arr['msg'] = 'correct values!';

header('Content-Type: application/json');       
echo json_encode($arr);

And here is my .js file:

$.ajax({
    url :  file.php,
    type : 'GET',
    data : {"arg1": 1, "arg2": 1},
    dataType : 'JSON',
    success : function (data) {
        alert(data.msg);
    }
});

As I expect, after executing those code, it should shows a alert containing this message: wrong values! . But it doesn't work, Why?

Note1: If I pass data : {"arg1": 1, "arg2": 0} , It will show a alert containing correct values! as well. Now I think the problem is that if -statement in the .php file.

Note2: The above code worked fine already. But now I updated my Xampp and after updating that problem has occurred.

Answer 1

Your if statement states that arg1 must not be 1 and arg2 must not be 0 . When you pass data for arg1=1 and arg2=1 that statement will not work. Your problem is in your if statement. If you want your if statement work for each condition you should use or statement like this ||

if ($arg1 !==1 || $arg2 !==0) {//i made this condition *or* check this 
  $arr['msg'] = 'wrong values!';
  header('Content-Type: application/json');     
  echo json_encode($arr);
  exit();
}

Answer 2

More or less just putting together all the comments:

• instead of $arg1...&&$arg2... use the logical-or operator
• _GET contains strings (and arrays) and !== checks the data type first, hence $_GET['foo']!==1 will never be true

Because php's implicit type-juggling might consider values equal to 0 or 1 other than you'd expect, I'd suggest you keep the strict comparison (=== or !==).
You apparently want to check some numbers, so I threw intval() in and kept the strict comparison. But you could instead test if ('1'!==$_GET['arg1'] || '0'!==$_GET['arg2']) .

<?php
if ( !isset($_GET['arg1'], $_GET['arg2']) ) {
    $response = [
        'status'=>'error',
        'msg'=>'missing parameter(s)'
    ];
}
else {
    // you could add another test like http://docs.php.net/ctype_digit here first
    $arg1 = intval($_GET['arg1']);
    $arg2 = intval($_GET['arg2']);

    if ( 1!==$arg1 || 0!==$arg2 ) {
        $response = [
            'status' => '...',
            'msg' => 'wrong values!'
        ];
    }
    else {
        $response = [
            'status' => '...',
            'msg' => 'correct values!'
        ];
    }
}

header('Content-Type: application/json');     
echo json_encode($arr);

---side note---
I could make an argument for something like

$arguments = [
  intval($_GET['arg1']), // maybe even 'arg1'=>intval($_GET['arg1'])
  intval($_GET['arg2'])
];
if ( array(1,0)!==$arguments ) {

....but no, I just mention it ;-)

Answer 3

You want || (or), not && (and), in your conditional. As currently written, it will return an error only if both values are incorrect.