haodazhiy啊 / Getting Started with a User Script

// ==UserScript==
// @namespace     https://openuserjs.org/users/haodazhiy啊
// @name          Getting Started with a User Script
// @description   Showing the current basic and recommended format for a User script.
// @copyright     2021, haodazhiy啊 (https://openuserjs.org/users/haodazhiy啊)
// @license       MIT
// @version       0.0.0
// @include       https://**/*
// @grant none
// ==/UserScript==

// ==OpenUserJS==
// @author haodazhiy啊
// ==/OpenUserJS==

/**
  *
  * Please begin typing or paste your User script now.
  *
  */

function GetUrlParam(paraName) {
    var url = document.location.toString();
    var arrObj = url.split("?");
  
    if (arrObj.length > 1) {
        var arrPara = arrObj[1].split("&");
        var arr;
  
        for (var i = 0; i < arrPara.length; i++) {
          arr = arrPara[i].split("=");
  
          if (arr != null && arr[0] == paraName) {
            return arr[1];
          }
        }
        return "";
      }
      else {
        return "";
      }
      }
  
  function tojiuse() {
    const is91 = window.location.href.includes('www.91porn.com')
    if(is91) {
      var div=document.createElement("div");
      div.innerText = "九色";
      div.style = `position: fixed;top: 10px;right: 10px;z-index: 30000;background: #777;color: #fff;padding: 5px 10px;`
      div.addEventListener('click', () => {
        const viewkey = GetUrlParam('viewkey')
        if(viewkey) {
          window.location.href = 'https://jiuse.me/video/view/' + viewkey
        }
      })
      document.body.appendChild(div)
      const viewkey = GetUrlParam('viewkey')
      if(viewkey) {
        window.location.href = 'https://jiuse.me/video/view/' + viewkey
      }
    }
  }
  
  (function() {
    tojiuse();
  })()