angularjs - 如果在下拉菜单中未选择任何内容，则禁用按钮

Question

当下拉菜单中未选择任何内容时，应禁用该按钮。我怎样才能做到这一点？

<select size='1' id="action" ng-model="ak.action">
    <option value='1'>RED</option>
    <option value='2'>BLUE</option>
</select>

<div>
    <button type="button" ng-Click="ak.save()" >SAVE</button>
</div>

Answer 1

尝试ng-disabled="!ak.action || ak.action.length == 0"在按钮上使用。尽管select在您的情况下将始终有一个选定的项目......

<select size='1' id="action" ng-model="ak.action">
        <option value='1'>RED</option>
        <option value='2'>BLUE</option>
</select>

<div>
    <button ng-disabled="!ak.action || ak.action.length == 0" type="button" ng-click="ak.save()" >SAVE</button>
</div>