$ _GET在if语句中随机取消设置

Question

I'm sure there is a simple answer to this stupid problem but I have searched high and low and can not figure out why this wont work.

$tutorid = $_GET['userid'];

var_dump($tutorid);

//populate user tutoring subjects
if( isset($_POST['a'])) {
  $currentsubjects = get_current_user_subjects( $tutorid );
  unset($_POST['a']);
  echo json_encode($currentsubjects); return;
}

I have a simple AJAX function that sets $_POST['a'] equal to something. The var_dump($tutorid) properly displays the id from the url. However the $tutorid in the get_current_user_subjects is sending NULL.

If I try a var_dump like this to check $tutorid

$tutorid = $_GET['userid'];

//populate user tutoring subjects
if( isset($_POST['a'])) {
  echo json_encode($tutorid); return;
  // $currentsubjects = get_current_user_subjects( $tutorid );
  // unset($_POST['a']);
  // echo json_encode($currentsubjects); return;
}

Then I get NULL. If I hard code in a tutorid in the get_current_user_subjects( $tutorid ) (like add in 15 or something) the function returns data to console.log like expected but using the variable $tutorid stops it completely. I can't figure out why this is happening! Someone please enlighten me.

Here is the AJAX just incase. It works find on other pages so I am assuming the issue is with $_GET

$.ajax({
  url: 'profile.php',
  method: 'post',
  data: "a=true",
  dataType: 'json',
  success: function (x) {
    console.log(x);
  },
  error: function(a, b, c) {
    console.log(a);
    console.log(b);
    console.log(c);
  }

Answer 1

Maybe you can use this method. So you can POST the userid

$.ajax({
  url: 'profile.php',
  method: 'post',
  data: {a: a, userid:userid},
  dataType: 'json',
  success: function (x) {
    console.log(x);
  },
  error: function(a, b, c) {
    console.log(a);
    console.log(b);
    console.log(c);
  }

So in your form before the action. you can set userid in hidden form

<input type="hidden" name="userid" value="<?php echo $userid;?>" />