如果PHP响应等于某事，如何使jQuery警报

Question

I have this jQuery script:

$(document).ready(function(){
    $('#submitNewExam').click(function(e){
        e.preventDefault();
        var examName = $('#newExam').val();
        if ($.trim(newExam) != ''){
            $.post('functions/addExam.php', { newExam: examName }, function(data){
                console.log(data);
                if(data =='error'){
                    $('#notify').html(data);
                    $('.alert').toggle();
                }
            });
        }
        $('.add').toggle();
    });
    });

and this PHP:

if(isset($_POST['newExam'])){
    if(preg_match('/(<|>|"|%3c|%3e|%22)/', $_POST['newExam'])){
        $a = 'error';
        echo json_encode($a);
    } else {
        echo "something";
    }
}   

I'm able to output the response of PHP, what I'm not able to do is to make jQuery read that response and do something if the response in my example is equal to error. I have tried to encode the response in JSON and just to echo the response as a string, but none of those is working. In the console.log I can see the response but jQuery is doing nothing.

Answer 1

Without parsing of the json, your string will contain quotes: "error".

You can either manually parse the json or have jQuery do it automatically by specifying a data type:

$.post('functions/addExam.php', { newExam: examName }, function(data){
    console.log(data);
    if(data =='error'){
        $('#notify').html(data);
        $('.alert').toggle();
    }
}, 'json');
    ^^^^ here you specify the data type