JS not waiting for prototype Ajax.Request to complete before proceeding

I am using prototype.js for this process.

I have a script that check a login form and uses JS to go check the form be for submitting. Code below. Problem is the script id not waiting for the result of the Ajax before proceeding so JS returns true before the Ajax request is even finished. In my test code below I get the alert with "HERE" before I get the result form the Ajax. How can I set my tell my script to wait for the result from Ajax.Request?


function check_login(me) {
      var email = $F('loginEmail');
      var password = $F('loginPasswd');
      if(email=='') {
            alert('You must enter a your email address to sign up.');
            return false;
      } else if(password=='') {
            alert('You must enter a your password to sign up.');
            return false;
      } else {
            new Ajax.Request("/ajax/login.php", {
                  method: 'post',
                  parameters: { email: email, passwd: password },
                  afterFinish: function(transport) {
                        var data = transport.responseText;
                        if(data==0) {
                              alert('zero');
                              $('loginError').update('Your email and password are not in our system.');
                              new Effect.Shake($('loginForm'));
                              return false;
                        } else {
                              alert('passed?');
                              return false;                        
                        }
                  }
            });
            alert("HERE");
      }
}


Thanks!