How does the front-end js tell whether users follow the official account (in Wechat's browser) and have already got openid and access_token? is there any example?

means that when the user enters the program we developed on the official account (web page, not Mini Program), we need to judge whether the user has followed the official account, and if not, a pop-up window will pop up. I have found a lot on the Internet, but there are no examples. I don"t quite know how to call that interface. I ask all of you to answer your doubts. Thank you very much. The following is the code and error report. Ps (I heard that there are two interfaces for obtaining user information. I have tried one and reported an error. Please post an error message picture below.)

data() {
  return {
    show: false
  }
},
mounted() {
  this.tanchu()
},
methods: {
  tanchu() {
    let openid = window.sessionStorage.getItem("openid")
    let access_token = window.sessionStorage.getItem("access_token")
    // let url = "https://api.weixin.qq.com/sns/userinfo?access_token=" + access_token + "&openid=" + openid +
    //   "&lang=zh_CN"
    let url = "https://api.weixin.qq.com/cgi-bin/user/info?access_token=" + access_token + "&openid=" + openid +
      "&lang=zh_CN"
    const res = this.$http.get(url)
    console.log(res);
    if (res.subscribe == 0) {
      setTimeout(() => {
        this.show = true
      }, 3000);
    } else {
      this.show = false
    }
  },
  close() {
    this.show = false
  }
},


< hr >


this front-end js cannot be done, it can only be obtained from the back-end, and then make a judgment. The backend has been resolved

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-7c2e57-975f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-7c2e57-975f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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