如何识别浏览器的类型
navigator 和 screen
// navigator
const ua = navigator.userAgent
console.log(ua.indexOf('Chrome')) // 81
// screen
console.log(screen.width,screen.height) // 1920 1080
navigator 和 screen
// navigator
const ua = navigator.userAgent
console.log(ua.indexOf('Chrome')) // 81
// screen
console.log(screen.width,screen.height) // 1920 1080