Angular+Bootstrap input validation error class

Question

I'm trying to make example from this article using angular+bootstrap. I have this working code:

<div ng-controller="Ctrl">
    <br>
    <hr>

    <form name="signup_form" novalidate ng-submit="signupForm()">
        <fieldset>
            {{' signup_form.submitted \''+signup_form.submitted+ '\' ' }}<br>
            {{' submitted \''+submitted+ '\' ' }}<br>
            {{' $scope.signup_form.$valid \''+signup_form.$valid+ '\'' }}

            <div class="control-group" ng-class="{error: signup_form.name.$dirty && signup_form.name.$invalid}">
                <legend>Signup</legend>
                <div class="row">
                    <div class="span12">
                        <label>Your name</label>
                        <input type="text"
                               placeholder="Name"
                               name="name"
                               ng-model="signup.name"
                               ng-minlength=3
                               ng-maxlength=20 required/>
                    </div>
                </div>
            </div>
            <button type="submit" class="button radius">Submit</button>
        </fieldset>
    </form>

</div>

http://jsfiddle.net/cQ324/3/

The questions are:

1. This piece of code:

   <div class="control-group" ng-class="{error: signup_form.name.$dirty && signup_form.name.$invalid}">
   

   does not look very nice. I feel it's not good practice to do it this way. How could it be more easy and correct?

2. If I press input field, I instantly got red borders. I found this problem github.com/twbs/bootstrap/issues/1675, but it is a very old thread. What's the best and correct way to avoid this red box on empty field click?

Any overall code suggestions are welcome. ty! )

Answer 1

I've done things like this in forms I've created:

<div class="form-group col-md-3 input-group-lg" ng-class="{true: 'has-error',false: 'is-required'}[createContacts.proposer.$dirty && createContacts.proposer.$invalid]">
    <label class="control-label" for="proposer">Name *</label>
    <input type="text" class="form-control" name="proposer" id="proposer" placeholder="First & Last Name" ng-model="proposer.name" required>    
    <span class="help-block" ng-show="createContacts.proposer.$dirty && createContacts.proposer.$error.required">Proposer's name is required.</span>
</div>

ng-class="{true: 'has-error',false: 'is-required'}[createContacts.proposer.$dirty && createContacts.proposer.$invalid]"

is-required class is not a part of bootstrap, its a class I created to color code required objects when not in error.