AngularJs Custom directive not binding with “textarea”

Question

I make a custom directives for prevent enter key. It work fine for only "input" element, but it's not binding on "textarea". here is my js

function inputFocus() {
    return {
        restrict: 'E',
        require: '?ngModel',
        link: function ($scope, elem, attrs) {
            elem.bind('keydown', function (event) {
                var code = event.keyCode || event.which;
                if (code === 13) {
                    $scope.$apply(function () {
                        $scope.$eval(attrs.inputFocus);
                    });
                     event.preventDefault();
                }
            });
        }
    }
}

And:

<textarea class="form-control" name="UserName" maxlength="50" rows="2" 
          ng-model="UserName" tabindex="2" required>
</textarea>

Answer 1

I found my mistake by asking your question :) I give directives name by "input" so that it bind with all input elements. So, have to bind this also with "textarea" like

angular.module('apanelApp').directive('textarea', inputFocus);

Thanks to all for response.