封装

function cookie(name, value, options) {
  if (typeof value != 'undefined') {
    options = options || {};
    if ((value = null)) {
      value = '';
      options.expires = -1;
    }
    var expires = '';
    if (
      options.expires &&
      (typeof options.expires == 'number' || options.expires.toUTCString())
    ) {
      var date;
      if (typeof options.expires == 'number') {
        date = new Date();
        date.setTime(date.getDate() + options.expires * 24 * 60 * 60 * 1000);
      } else {
        date = option.expires;
      }
      expires = ';expires=' + date.toUTCString();
    }
    var path = options.path ? ';path=' + options.path : '';
    var domain = options.domain ? ';domain=' + options.domain : '';
    var secure = options.secure ? ';secure' : '';
    document.cookie = [
      name,
      '=',
      encodeURIComponent(value),
      expires,
      path,
      domain,
      secure,
    ].join('');
  } else {
    var CookieValue = null;
    if (document.cookie && document.cookie != '') {
      var cookie = document.cookie.split('');
      for (var i = 0; i < cookie.length; i++) {
        var cookie = (cookie[i] || '').replace(/^\s+|\s+$/g, '');
        if (cookie.substring(0, name.length + 1) == name + '=') {
          cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
          break;
        }
      }
    }
    return cookieValue;
  }
}