<select class="form-control-inline" ng-model="currentMatrixTemplate.rowAttributeId" required ng-change="changeAttribute('row', currentMatrixTemplate.rowAttributeId, {{currentMatrixTemplate.rowAttributeId}})" ng-options="attribute.value as attribute.text for attribute in metaData.attributes |filter: { value: '!' + currentMatrixTemplate.columnAttributeId }"> <option value="" disabled> @String.Format(Labels.selectX, Labels.attribute)...</option> </select>I want to make sure that user selected a value which will be a number greater than 0. I don't want the Add button to become enabled until it's done.