AngularJS validation with no enclosing

You may use the ng-form angular directive (see docs here) to group anything, even outside a html form. Then, you can take advantage from angular FormController.

<div class="form-group" ng-form name="myForm">
    <input name="myInput" type="text" class="form-control" ng-model="bindTo" ng-maxlength="5">
    <span class="error" ng-show="myForm.myInput.$error.maxlength">Too long!</span>
</div>

Example