CSS 實現必填項前的紅*

效果圖：

 

html

<view class="login-input login-margin-b">
		<view class="input-title redDot"></span>暱稱：</view>
		<input type="text" placeholder="" id="nickname" v-model="payload.nickname" />
</view>

 css

.redDot:before {
        content: '*';
        color: red;
    }