cookie的封装

1.*设置cookie   name 键   val 值    exday 有效期（天） #有效期并不是必选项，也可以不设置
function setCookie (name, val, exday) {
   let d = new Date()
   let expires = ''
   if (exday) {
    d.setTime(d.getTime() + (exday * 24 * 60 * 60 * 1000))
    expires = '; expires=' + d.toGMTString()
   }
   document.cookie = name + '=' + val + expires
}

2. 获取cookie
function getCookie (name) {
   let data = ''
   if (document.cookie) {
    let arr = document.cookie.split(';')
    for (let str of arr) {
       let temp = str.split('=')
       if (temp[0].replace(/(^\s*)/g, '') === name) {
          data = unescape(temp[1])
         break
       }
     }
   } else {
    console.warn('cookie不存在')
  }
  return data
}

3.清除cookie值
function removeCookie (name) {
   let exp = new Date()
   exp.setTime(exp.getTime() - 1)
   let val = getCookie(name)
   if (val != null) document.cookie = name + '=' + val + ';expires=' + exp.toGMTString()
  }