gistfile1.txt

<form class="form-horizontal" id="comment-form" ng-show="CommentAPI.connected">
  <fieldset>
    <legend>Post a comment</legend>
    <div class="form-group">
      <label for="postcomment-homepage" class="col-lg-2 control-label">Homepage</label>
      <div class="col-lg-10">
        <input class="form-control" id="postcomment-homepage" placeholder="Homepage" type="url"
               maxlength="150" ng-model="comment.homepage">
      </div>
    </div>
    ...
    <div class="form-group">
      <div class="col-lg-10 col-lg-offset-2">
        <button type="submit" class="btn btn-primary"
                ng-click="submit(comment)"
                ng-disabled="submitting">Submit Comment</button>
        <img src='{{ path }}/spinner.gif' class="submitting-spinner" ng-show="submitting" />
      </div>
    </div>
  </fieldset>
</form>



app.controller('PostCommentController', [
               '$scope', '$filter', '$sanitize', 'Config', 'Comment',
               function($scope, $filter, $sanitize, Config, Comment)
{
  $scope.comment = {
    homepage: null,
  };
  $scope.submit = function(comment) {
     # Here, comment.homepage is either null (if the input was never touched)
     # a valid url (url entered) or undefined (entered `javascript:` url).
     # Ideally, I'd like to validate the input so that either blank or a valid
     # URL are valid, or angular validation fails (and 'undefined' can't happen
     # here any more.)
  }
}