JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<div ng-app="myApp" ng-controller="MyCtrl">
    {{myModel}}
    <select ng-model="myModel">
        <option value="1">option 1</option>
        <option value="2">option 2</option>
        <option value="3">option 3</option>
    </select>
    <button onclick="updateDropDownDirectly(1)">1</button>
    <button onclick="updateDropDownDirectly(2)">2</button>
    <button onclick="updateDropDownDirectly(3)">3</button>
</div>

JavaScript

angular.module("myApp", []);

function MyCtrl($scope)
{
    $scope.myModel = 2;
}

function updateDropDownDirectly(value)
{
    $("select").val(value);
}