PHP形式不断给我同样的答复

Question

very short simple quiz app. browser keeps returning Correct as a response, even though it is not correct.

<?php
$answer = (isset($_POST['answer']));`
if ($answer == "Dagny Taggart")`
{
echo "Correct";
 } else {
 echo "wrong";
 }
 ?>

Answer 1

Try this. You're currently setting $answer to isset($_POST['answer'] , meaning as long as $_POST['answer'] is set, you're $answer is going to be TRUE . I would check if it's set and then set it to the $_POST value.

<?php
if(isset($_POST['answer'])) {
    $answer = $_POST['answer'];
    if ($answer == "Dagny Taggart")
    {
        echo "Correct";
    } else {
        echo "wrong";
    }
} else {
// Do something?
}

?>

Answer 2

isset returns a boolean ( true or false ) value. So your test will always fail because true != 'Dagny Taggart'

Add this ternary and it will work

$answer = (isset($_POST['answer'])) ? $_POST['answer'] : '';