angucomplete-alt标签＆＃39;必需＆＃39;在一种形式

Question

在form标签中包含以下指令，但不确定为什么field-required不起作用且表单已提交。

<form>
    <angucomplete-alt id="fromStationInput"
          placeholder="Enter from location"
          pause="100"
          selected-object="fromSelected"
          local-data="mapToArray"
          search-fields="fromLocation"
          local-search="localSearch"
          title-field="cityName"
          minlength="1"
          input-class="input-text full-width" ng-model="fromLocation" match-   class="highlight"
  field-required="true"
  input-name="cityName"/>
</form>