title: How to disable submit button if checkbox and dropdown menu wasn't filled yet?
body: <p>I am using 2 different functions for checkbox and dropdown<br/>
  Checkbox function:</p>
  
  <pre><code>$(function () {
      $('.cb').change(function () {
          if ($(this).is(":checked")) {
              $('#add').removeAttr('disabled');
          }
          else {
              var isChecked = false;
              $('.cb').each(function () {
                  if ($(this).is(":checked")) {
                      $('#add').removeAttr('disabled');
                      isChecked = true;
                  }
              });
              if (!isChecked) {
                  $('#add').attr('disabled', 'disabled');
              }
          }
      })
  });
  </code></pre>
  
  <p>Dropdown function:</p>
  
  <pre><code>$("#tripSelect").on('change',function(){
     if($(this).find('option:selected').text()=="Choose Trip")
         $("#add").attr('disabled',true)
     else
         $("#add").attr('disabled',false)
  });
  </code></pre>
  
  <p>They don't work with each other. I tried combining them but it's not working for me. I wanted to disable the <code>#add</code> button if not at least 1 checkbox is checked and the dropwdown says anything but <code>Choose Trip</code>. If 1 of the them is false then the button is disabled.</p>