I’m using the following code on a HABPanel widget to show a “Textbox” (empty space taking the text) followed by a button that hands the text to a string item (SayCommand).
<div class="form-group">
<input type="text" class="form-control" no-snap-drag="true"
ng-model="myvalue" ng-value="itemValue('SayCommand')"></input>
<button type="button" class="btn btn-primary"
ng-click="sendCmd('SayCommand', myvalue)">Sag es!</button>
</div>