scinote-web/app/assets/javascripts/sitewide/form_errors.js

// Define AJAX methods for handling errors on forms
$.fn.render_form_errors = function(model_name, errors, clear) {
  if (clear || clear === undefined) {
    this.clear_form_errors();
  }
  $(this).render_form_errors_no_clear(model_name, errors, false);
};

$.fn.render_form_errors_input_group = function(model_name, errors) {
  this.clear_form_errors();
  $(this).render_form_errors_no_clear(model_name, errors, true);
};

$.fn.render_form_errors_no_clear = function(model_name, errors, input_group) {
  var form = $(this);

  $.each(errors, function(field, messages) {
    input = $(_.filter(form.find('input, select, textarea'), function(el) {
      var name = $(el).attr('name');
      if (name) {
        return name.match(new RegExp(model_name + '\\[' + field + '\\(?'));
      }
      return false;
    }));
    input.closest('.form-group').addClass('has-error');
    var error_text = '<span class="help-block">';
    error_text += (_.map(messages, function(m) {
      return m.charAt(0).toUpperCase() + m.slice(1);
    })).join('<br />');
    error_text += '</span>';
    if (input_group) {
      input.closest('.form-group').append(error_text);
    } else {
      input.parent().append(error_text);
    }
  });
};

$.fn.clear_form_errors = function() {
  $(this).find('.form-group').removeClass('has-error');
  $(this).find('span.help-block').remove();
};

$.fn.clear_form_fields = function() {
  $(this).find("input")
    .not("button")
    .not('input[type="submit"], input[type="reset"], input[type="hidden"]')
    .not('input[type="radio"]') // Leave out radios as this messes up Bootstrap btn-groups
    .val('')
    .removeAttr('checked')
    .removeAttr('selected');
};

// Add JavaScript client-side upload file size checking
// Callback function can be provided to be called
// any time at least one file size is too large
$.fn.add_upload_file_size_check = function(callback) {
  var form = $(this);

  if (form.length && form.length > 0) {
    form.submit(function (ev) {
      var fileInputs = $(this).find("input[type='file']");
      if (fileInputs.length && fileInputs.length > 0) {
        var cntr = 0;
        _.each(fileInputs, function(fileInput) {
          if (typeof (fileInput.files) != "undefined") {
            var size = parseInt(fileInput.files[0].size);
            if (size > 52428800) {
              cntr++;
              var input = $(fileInput);
              var existingError = input.parent().find("[data-error='file-size']");
              if (!(existingError.length && existingError.length > 0)) {
                input.closest('.form-group').addClass('has-error');
                input.parent().append(
                  "<span class='help-block' data-error='file-size'>Must be less than 50 MB</span>"
                );
              }
            }
          }
        });

        if (cntr > 0) {
          // Don't submit form
          ev.preventDefault();
          ev.stopPropagation();

          if (callback) {
            callback();
          }

          return false;
        }
      }
    });
  }
};

// If any of tabs has errors, add has-error class to
// parent tab navigation link
function tabsPropagateErrorClass(parent) {
  var contents = parent.find("div.tab-pane");
  _.each(contents, function(tab) {
    var $tab = $(tab);
    var errorFields = $tab.find(".has-error");
    if (errorFields.length > 0) {
      var id = $tab.attr("id");
      var navLink = parent.find("a[href='#" + id + "'][data-toggle='tab']");
      if (navLink.parent().length > 0) {
        navLink.parent().addClass("has-error");
      }
    }
  });
  $(".nav-tabs .has-error:first > a", parent).tab("show");
}