jQuery检查输入是否为空

Question

I am trying to get it where, if there is value in the input, go ahead and do your thing but if there isn't, don't do anything. I keep getting getting it where, if there is nothing in the input, a failure message occurs but only if I hit the enter key
jsfiddle.net/BBaughn/8ovrmhgp click the space in the lower right corner, then press enter. It shouldn't pop up, because the input is not focused.

login/failure jQuery:

$(document).ready(function(){
  $('.btn1').on('click', function(){
    var login = [marion, 'FATHER1'];

    var marion = $('#logging').val();
    marion = marion.toUpperCase();

    if (marion !== 'FATHER1' && $('#logging').val()) {
      alert('Login Failed');
  } else if (marion === 'FATHER1' && $('#logging').val()) {
    $('.notify').css('margin-top', '0');
      $('#logging').val('');
  }

  });
  $('.exit').on('click', function(){
    $('.notify').slideUp('slow');
  });
});

Answer 1

if you just want to check if an input is empty, I'm guessing #logging is the input:

$('.btn1').on('click', function(){
    var marion = $('#logging').val();
    if (marion == '') {
       //this means the input value was empty
    }
});

Answer 2

Ok, I think I get what you mean now. You're checking the entire document for keypresses as is, you need to check the input only. I think this is a good solution to do that:

$('.login input').keypress(function (e) {
    if (e.which == 13 && !$('#logging').val()) {
        e.PreventDefault();
    } else if (e.which == 13 && $('.btn1').focus()) {
        $('.btn1').click();
    }
});

Working Fiddle here

Answer 3

if the length is equal zero, that means the field is empty. It works after adding length === 0 check, please try this,

if (e.which == 13 && $('.btn1').val().length === 0) {
    e.preventDefault();
} else if (e.which == 13 && $('.btn1').focus()) {
    $('.btn1').click();
}

Answer 4

$(document).ready(function(){
  $('.btn1').on('click', function(){
    var login = [marion, 'FATHER1'];

    var marion = $('#logging').val();
    marion = marion.toUpperCase();

    if (marion !== 'FATHER1' && $('#logging').val()) {
      alert('Login Failed');
  } else if (marion === 'FATHER1' && $('#logging').val()) {
    $('.notify').css('margin-top', '0');
      $('#logging').val('');
  }

  });
  $('.exit').on('click', function(){
    $('.notify').slideUp('slow');
  });
});

I didn't realize that my if statement was if the input wasn't detecting the right login, so it didn't matter if it was out of focus. Now it says "if it's not FATHER1 and there is value in the input only, then send this alert"