Javascript 如何为textarea创建字符计数器？（角度）

代码：

    <div class="form-group">
      <label class="control-label" for="content">Content</label>
      <textarea name="content" data-ng-model="vm.article.content" id="content" class="form-control" cols="30" rows="10" placeholder="1400 characters long at least" required ng-minlength="1400" ng-maxlength="14000" highlight-on-error></textarea>
        <!--counter-->
      <br>
      <span class="form-help">{{1400-vm.article.content.length}}         
       Characters</span>
      <div ng-messages="vm.form.articleForms.content.$error" role="alert">
        <p class="help-block error-text" ng-message="required">Article title is required.</p>
      </div>
    </div>

内容


{{1400 vm.article.content.length}
人物
需要文章标题

---

情况：

    <div class="form-group">
      <label class="control-label" for="content">Content</label>
      <textarea name="content" data-ng-model="vm.article.content" id="content" class="form-control" cols="30" rows="10" placeholder="1400 characters long at least" required ng-minlength="1400" ng-maxlength="14000" highlight-on-error></textarea>
        <!--counter-->
      <br>
      <span class="form-help">{{1400-vm.article.content.length}}         
       Characters</span>
      <div ng-messages="vm.form.articleForms.content.$error" role="alert">
        <p class="help-block error-text" ng-message="required">Article title is required.</p>
      </div>
    </div>

我试图在提交时显示一条错误消息，如果ng消息的字数过低：错误消息不会出现

我还试图实时更新文本区域的字数。它不吐

我做错了什么

---

参考资料：

    <div class="form-group">
      <label class="control-label" for="content">Content</label>
      <textarea name="content" data-ng-model="vm.article.content" id="content" class="form-control" cols="30" rows="10" placeholder="1400 characters long at least" required ng-minlength="1400" ng-maxlength="14000" highlight-on-error></textarea>
        <!--counter-->
      <br>
      <span class="form-help">{{1400-vm.article.content.length}}         
       Characters</span>
      <div ng-messages="vm.form.articleForms.content.$error" role="alert">
        <p class="help-block error-text" ng-message="required">Article title is required.</p>
      </div>
    </div>

---

p.S.：

    <div class="form-group">
      <label class="control-label" for="content">Content</label>
      <textarea name="content" data-ng-model="vm.article.content" id="content" class="form-control" cols="30" rows="10" placeholder="1400 characters long at least" required ng-minlength="1400" ng-maxlength="14000" highlight-on-error></textarea>
        <!--counter-->
      <br>
      <span class="form-help">{{1400-vm.article.content.length}}         
       Characters</span>
      <div ng-messages="vm.form.articleForms.content.$error" role="alert">
        <p class="help-block error-text" ng-message="required">Article title is required.</p>
      </div>
    </div>

我使用的是mean.js

工作正常：

内容


{{1400 vm.article.content.length}
人物
需要文章标题

但我需要ng minlength。@Coder1000您应该添加验证，如min allow 1400 characterWhere？你能解释一下吗？@Coder1000检查一下-这在这种情况下没有帮助：ng消息“required”没有显示在我的代码中，例如：/