<u-input :showWordLimit="true" maxlength="200" v-model="form.faultDescription" height="80" :auto-height="true"
                     type="textarea" placeholderStyle='color:#828282' @input="inputChange($event,'faultDescription')" placeholder="请输入故障描述" />

inputChange(e,attr){
    if(e.length>20){
         setTimeout(()=>{
              this.form[attr]=e.slice(0,20)
           },0)
        }
                
},

双向绑定时，页面渲染数据不是实时的，稍微有延迟