Disable submit if inputs empty jquery

问题:

Disclaimer: I know there are quite a few questions out there with this topic and it has been highly addressed, though I need assistance in my particular case.

I am trying to check if the input values are empty on keyup then disable the submit button.

My HTML snippet:

<div class='form'>
  <form>
    <div class='field'>
      <label for="username">Username</label>
      <input id="username" type="text" />
    </div>
    <div class='field'>
      <label for="password">Password</label>
      <input id="password" type="password" />
    </div>
    <div class='actions'>
      <input type="submit" value="Login" />
    </div>
  </form>
</div>

I have used the example answer from here with some modifications:

(function() {
    $('.field input').keyup(function() {

        var empty = false;
        $('.field input').each(function() {
            if ($(this).val() == '') {
                empty = true;
            }
        });

        if (empty) {
            $('.actions input').attr('disabled', true);
        } else {
            $('.actions input').attr('disabled', false);
        }
    });
})()

Any help would be greatly appreciated!

回答1:

I would suggest disabling the button by default. I would also look at the length of the .val(), not check for an empty string. Lastly, I think document.ready() is much more readable than your existing code: Here is the full code:

HTML

<div class='form'>
  <form>
    <div class='field'>
      <label for="username">Username</label>
      <input id="username" type="text" />
    </div>
    <div class='field'>
      <label for="password">Password</label>
      <input id="password" type="password" />
    </div>
    <div class='actions'>
      <input type="submit" value="Login" disabled="disabled" />
    </div>
  </form>
</div>​

JS/jQuery

$(document).ready(function() {
    $('.field input').keyup(function() {

        var empty = false;
        $('.field input').each(function() {
            if ($(this).val().length == 0) {
                empty = true;
            }
        });

        if (empty) {
            $('.actions input').attr('disabled', 'disabled');
        } else {
            $('.actions input').removeAttr('disabled');
        }
    });
});

Here's a working fiddle.

回答2:

I use this in my project and it succes.

$(document).ready(function() {
  $('.field').keyup(function() {

    var empty = false;
    $('.field').each(function() {
        if ($(this).val().length == 0) {
            empty = true;
        }
    });                   

    if (empty) {
        $('.actions[type="submit"]').attr('disabled', 'disabled');
    } else {
        $('.actions[type="submit"]').removeAttr('disabled');
    }                
  });
});

回答3:

You can write it like that instead of use "if" conditions

$('button[type=submit]').prop('disabled', empty);