1

<p class="updataPhone" v-if="hidshow"> 手机号填错了? </p>

2

data () {
    return {
        docmHeight:0,  //默认屏幕高度
        hidshow:true  //显示或者隐藏footer
    };
  },

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 mounted() {
    this.docmHeight = document.documentElement.clientHeight;//获取当前屏幕高度
    window.onresize = () => {//屏幕高度变化时判断
      return (() => {
        let showHeight = document.body.clientHeight;
        this.hidshow = this.docmHeight > showHeight ? false : true;
      })();
    };
  }

完美解决~~欧耶欧耶欧耶