JS判断当前环境为微信，判断是Android还是IOS

判断是否为微信环境

let wx = navigator.userAgent.toLowerCase();
if (wx.match(/MicroMessenger/i) == "micromessenger") {
     alert('当前环境为微信环境')
 }

判断是Android还是IOS

let web = navigator.userAgent;
//android终端
let isAndroid = web.indexOf('Android') > -1 || web.indexOf('Adr') > -1;
      //ios终端
let isiOS = !!web.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/);
if(isAndroid){
 alert('android')
}else if(isiOS){
  alert('ios')
}