发送信件时必须要选择一项，并且内容描述不能为空，这个应该怎么判断并绑定发送事件呢（：| ？

Question

<view class="content">
        <view class="list-box">
            <view v-for="(item,index) in list" :key="index" @click="choice(index,item)"
                :class="[style[index]==item?'selde':'noselde']">
                {{item}}
            </view>
        </view>
        <view class="textarea_box">
            <textarea class="textarea" placeholder="请您描述一下您的留言" maxlength="500" @input="descInput" v-model="desc" />
            <view class="num">{{ desc.length }}/500</view>
        </view>
        <easy-upload :dataList="dataList" uploadUrl="https://wmcs.jlbstv.com/index.php?m=api&c=v1.Api&a=upload_head_pic&_ajax=1"
            deleteUrl='' :types="types" @successImage="successImage"
            @successVideo="successvideo" @delImage="delImage" autoUpload="true" uploadCount="9"/>
        <button type="primary" @click="postMail()">发 布</button>
    </view>

Answer 1

<button @click="style.length && desc.trim() && postMail()">发布</button>