角。如何在即时搜索中添加延迟?

My Html Form looks like

我的Html表单看起来是这样的

    <form class="navbar-form navbar-left" role="search" name="userName">
      <div class="form-group">
        <input type="text" class="form-control" placeholder="Search Git By Username" ng-model="user" ng-change="searchForUser()" autofocus>
      </div>
    </form>