jQuery addClass example

Change class name on click in jQuery

by Chris

HTML

<html>
    <head>
        <title></title>
        <style type="text/css">
        </style>
        <script type="text/javascript">
        $(document).ready(function() {
            $('#register').attr("disabled", true);
        });
        </script>
    </head>
    <body>
        <form>
        Username<br />
        <input type="text" id="user_input" name="username" /><br />
        Password<br />
        <input type="text" id="pass_input" name="password" /><br />
        Confirm Password<br />
        <input type="text" id="v_pass_input" name="v_password" /><br />
        Email<br />
        <input type="text" id="email" name="email" /><br />     
        <input type="submit" id="register" value="Register" />
        </form>
        <div id="test">
        </div>
    </body>
</html>

JavaScript

var fields = "#user_input, #pass_input, #v_pass_input, #email";

$(fields).on('change', function() {
    if (allFilled()) {
        $('#register').removeAttr('disabled');
    } else {
        $('#register').attr('disabled', 'disabled');
    }
});

function allFilled() {
    var filled = true;
    $(fields).each(function() {
        if ($(this).val() == '') {
            filled = false;
        }
    });
    return filled;
}