$(document).ready(function(){
     $("#login_input").blur
     (
         function(e)
         {
              if ($(this).val() != '')
                  $.post
                  (
                      "/ajax_response/user_exists.php",
                      {login: $(this).val()},
                      function(r)
                      {
                         var answer = $("answer", r).text()
                         if (answer == 1)
                         {

                             $("#user_exists_suc").hide();
                             $("#user_exists_err").show();
                         }
                         else
                         {
                             $("#user_exists_suc").show();
                             $("#user_exists_err").hide();
                         }
                      }
                  );

         }
     )


 });