js操作获取和设置cookie

/*cookie的三种操作：读取，写入，删除*/
var CookieUtil = {
  get:function(name){
    var cookieName = encodeURIComponent(name) + "=",
        cookieStart = document.cookie.indexOf(cookieName),
        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;
  },
  set:function(name,value,expires,path,domain,secure){
    var cookieText = encodeURIComponent(name) + "=" + encodeURIComponent(value);
    if (expires instanceof Date) {
      cookieText += ";expires=" + expires.toGMTString();
    }
    if (path) {
      cookieText += ";path=" + path;
    }
    if (domain) {
      cookieText += ";domain=" + domain;
    }
    if (secure) {
      cookieText += ";secure";
    }
    document.cookie = cookieText;
  },
  unset:function(name,path,domain,secure){
    this.set(name,"",new Date(0),path,domain,secure);
  }
};