Disabling submit button until all fields have values

formbutton.js

function buttonState(){
    $("input").each(function(){
        $('#register').attr('disabled', 'disabled');
        if($(this).val() == "" ) return false;
        $('#register').attr('disabled', '');
    })
}

$(function(){
    $('#register').attr('disabled', 'disabled');
    $('input').change(buttonState);
})

formbutton_b.js

var $input = $('input:text'),
    $register = $('#register');    
$register.attr('disabled', true);

$input.keyup(function() {
    var trigger = false;
    $input.each(function() {
        if (!$(this).val()) {
            trigger = true;
        }
    });
    trigger ? $register.attr('disabled', true) : $register.removeAttr('disabled');
});