Disable submit unless all required fields have values

disable_submit.coffee

# disable submit unless all fields with .require_field class have values
$(document).ready ->

  total_required_fields = 0
  
  $( ".required_field" ).each ->

    total_required_fields += 1
    
    if $(this).val().trim().length == 0
      $('[type="submit"]').attr("disabled", "disabled")
    else
      $('[type="submit"]').removeAttr("disabled", "disabled")

  $(".required_field").keyup ->

    filled_required_fields = 0
    
    $( ".required_field" ).each ->
      if $(this).val().trim().length > 0
        filled_required_fields +=1

    if filled_required_fields == total_required_fields
      $('[type="submit"]').removeAttr "disabled"
    else
      $('[type="submit"]').attr("disabled", "disabled")