1.BOM包含哪些知识点

navigator，screen，location，history

2.Navigator

const ua=Navigator.userAgent;

const isChorme=ua.indexof('Chrome');

console.log(isChorme);

3.Screen

console.log(screen.width);

console.log(screen.height);

4.location

console.log(location.href);

console.log(location.protocal);

console.log(location.pathname);

console.log(location.pathname);

console.log(location.hash);

5.history

history.back();

history.forward();