Regularly judge the built-in browser of QQ and the built-in browser of WeChat

let url = navigator.userAgent.toLowerCase();
//Use toLowerCase to convert all strings to lowercase for us to judge and use
if (url.indexOf("15b202 qq") > -1) {
  // Judge QQ built-in browser separately
  alert("QQ APP has a built-in browser, do what you want to do");
}
if (url.indexOf("micromessenger") > -1) {
  // Separately judge the WeChat built-in browser
  alert('WeChat's built-in browser, do what you want');
}
if (url.indexOf("15b202") > -1) {
  //Determine the built-in browser of WeChat and the built-in browser of QQ
  alert("QQ and WeChat have built-in browsers, do what you want");
}