浏览器本地存储 webStorage

localStorage

特点：关闭浏览器缓存数据还在，除非清除浏览器缓存或是调API

1. 添加：localStorage.setItem('key','value')
2. 读取：localStorage.getItem('key')
3. 删除：localStorage.removeItem('key')
4. 清空：localStorage.clear()

sessionStorage

特点：关闭浏览器数据清空了

1. 添加：sessionStorage.setItem('key','value')
2. 读取：sessionStorage.getItem('key')
3. 删除：sessionStorage.removeItem('key')
4. 清空：sessionStorage.clear()