How can I check email exists via a jquery keyup()?

Question

I have setup a jQuery keyup delay function to check the email typed into an input field.

It works fine after testing with an alert('Key pressed!');

But I want it to say, for example, 'Yes this email is associated with a user' OR 'Sorry, this email is not in our database' without submitting any page requests.

    var delay = (function(){
        var timer = 0;
        return function(callback, ms){
            clearTimeout (timer);
            timer = setTimeout(callback, ms);
        };
    })();
    $('input').keyup(function() {
        delay(function(){
            // check email exists and output result
            // Can I use PHP here? 
            // Can ajax/json help?
        }, 500 );
    });

I tried to check with php but this is rendered before the jQuery of course which is where I'm storing my email var.

After a few google searches it sounds like this may not be possible. Can anyone confirm or offer a solution?

Thanks

Answer 1

I would use an AJAX request to a PHP script that does the lookup, which might look something like this on the jQuery side after document ready:

// jquery
$('#email-input').live('change', function() {
    //ajax request
    $.ajax({
        url: "email_check.php",
        data: {
            'email' : $('#email-input').val()
        },
        dataType: 'json',
        success: function(data) {
            if(data.result) {
                alert('Email exists!');
            }
            else {
                alert('Email doesnt!');
            }
        },
        error: function(data){
            //error
        }
    });
});

With the example above your PHP would have to return json data once its done the email check based on the address, for example your email_check.php would contain:

// get email passed via AJAX
$email = $_GET['email'];

// do check
if ( email_exists($email) ) {
    $response->result = true;
}
else {
    $response->result = false;
}

// echo json
echo json_encode($response);

Hope that helps!