开发者工具RC Build (1.02.1911181)版本textarea，将调试基础库设为2.9.3时输入不监听，设为其他基础库就OK！

代码片段：

wxml:

<form bindsubmit="toSaveMedia">

<textarea name="article" value="{{ article }}" maxlength="500" placeholder-style="color:#999" placeholder="请属于对好友的祝福" bindinput="articleInput"></textarea>

<button formType="submit">保存</button>

</form>

js：

articleInput(e) {

let that = this;

console.warn(e.detail.value);

},