Untitled

//View
<!DOCTYPE html>
<html ng-app="app">
  <head>
  </head>
  <body>
<section ng-controller="tekkenCtrl">
  <input ng-model="hp"/>
  <div id="arena">
    <div class="row">
      <div id="infos-player1" class="infos-player col-xs-6">
        <div class="progress">
          <div class="progress-bar progress-bar-success" role="progressbar" aria-valuenow="10" aria-valuemin="0"
               aria-valuemax="100" style="width:{{hp}}%">
          </div>
        </div>
    </div>
  </div>
</section>
</body>
</html>

//JS
var app = angular.module('app', []);
app.controller("tekkenCtrl", function ($scope) {
  $scope.hp = 80;

  window.onkeydown = function (event) {
    var e = event || window.event;
    var key = e.which || e.keyCode;
    switch (key) {
      case 38://D
        console.log('haut');
        $scope.hp = $scope.hp + 1;
        console.log($scope.hp);
        break;
      case 40:
        console.log('bas');
        $scope.hp = $scope.hp - 1;
        console.log($scope.hp);
        break;
      default :
        return true;
    }
  }
});