js之cookie

JavaScript 设置、读取和删除并不是特别的直观方便，我们可以封装成函数来方便调用。
//创建cookie
function setCookie(name, value, expires, path, domain, secure) {
 var cookieText = encodeURIComponent(name) + '=' + encodeURIComponent(value);
 if (expires instanceof Date) {
  cookieText += '; expires=' + expires;
 }
 if (path) {
  cookieText += '; expires=' + expires;
 }
 if (domain) {
  cookieText += '; domain=' + domain;
 }
 if (secure) {
  cookieText += '; secure';
 }
 document.cookie = cookieText;
}
//获取cookie
function getCookie(name) {
 var cookieName = encodeURIComponent(name) + '=';
 var cookieStart = document.cookie.indexOf(cookieName);
 var cookieValue = null;
 if (cookieStart > -1) {
  var cookieEnd = document.cookie.indexOf(';', cookieStart);
 if (cookieEnd == -1) {
  cookieEnd = document.cookie.length;
 }
 cookieValue = decodeURIComponent(
  document.cookie.substring(cookieStart + cookieName.length, cookieEnd));
 }
 return cookieValue;
}
//删除cookie
function unsetCookie(name) {
 document.cookie = name + "= ; expires=" + new Date(0);
 }
 //失效天数，直接传一个天数即可
 function setCookieDate(day) {
 if (typeof day == 'number' && day > 0) {
  var date = new Date();
  date.setDate(date.getDate() + day);
 } else {
  throw new Error('传递的day 必须是一个天数，必须比0 大');
 }
 return date;
}