Question

I have the following function which I use to check whether or not an email address is already registered.

checkTaken() {
  var email_var = $('input#email').val();

  $.post("../includes/check_email.inc.php",{email:email_var} ,function(data) {
      var ret = data + "";
    if(ret=="true") {//if username not avaiable
      $('div#emailTaken').show();
      $('input#email').addClass('redBack');
      return false;
    } else {
      $('div#emailTaken').hide();
      $('input#email').removeClass('redBack');
      return true;
    }
  });
} 

When I call it using something like the following it works fine:

email.blur(checkTaken);

But when I do something like

var test1 = checkTaken();

or

if(chekTaken) {

something quirky happens. It enters the function, executes the $.post line, but then never enters the rest of the routine. Why is this? And how do I fix it?

As a note, when I call the function using the last two examples, I do get information back from the server as seen through firebug.If I add a watch for test1, it remains undefined.

Answer 1

That is happening because checkTaken() does not wait for the $.post to finish before returning, due to the fact that $.post will fire off an asynchronous request to the server. What you can do is use $.ajax instead and set the async option to false (bearing in mind that it will block the browser momentarily while it waits for the request completes).