Javascript 如何关闭md select on按钮在md select内单击？

如何关闭md选择窗口内的md选择按钮

JS

$scope.closeSelectBox = () => {
  var esc = jQuery.Event("keydown");
  esc.which =  27
  esc.keyCode = 27
  $(document).trigger(esc)
}

HTML

<md-input-container style="max-width: 150px; width: 150">
  <label>Helper:</label>
  <md-select ng-model='vm.selectedHelpers' multiple>
    <md-select-header style="height: 25px">
      <md-button ng-click="closeSelectBox()">Close</md-button>
    </md-select-header>
    <md-option ng-repeat='item in vm.helpers' ng-value='item'>
      {{item.name}}
    </md-option>
  </md-select>
</md-input-container>

帮手：
接近
{{item.name}

已解决 只需点击md背景即可触发

$("md-backdrop").trigger ("click")

已解决 只需点击md背景即可触发

$("md-backdrop").trigger ("click")