JSFiddle - React, Tailwind, and code Playground
HTML
<div ng-app ng-controller="Controller">
<select ng-model="myDropDown">
<option value="one">One</option>
<option value="two">Two</option>
<option value="three">Three</option>
</select>
<input ng-show="myDropDown=='two'" type="text">
</div>
JavaScript
function Controller ($scope) {
$scope.myDropDown = 'one';
}