javascript中cookie常用操作

//写cookies
function setCookie(c_name, value, expiredays){
 　　　　var exdate=new Date();
　　　　exdate.setTime(exdate.getTime() + expiredays*24*60*60*1000);
　　　　document.cookie=c_name+ "=" + escape(value) + ((expiredays==null) ? "" : ";expires="+exdate.toGMTString());
 　　}
 
//写cookies（设置作用域）
function setCookie(name,value){
var Days = 30;
var exp = new Date();
exp.setTime(exp.getTime() + Days*24*60*60*1000);
let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)  //设置为一级域名
document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString()+";domain="+hostname+";path=/";
}

  
//读取cookies
function getCookie(name)
{
 var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
  
 if(arr=document.cookie.match(reg))
  
  return (arr[2]);
 else
  return null;
}
 
//删除cookies
function delCookie(name)
{
 var exp = new Date();
 exp.setTime(exp.getTime() - 1);
 var cval=getCookie(name);
 if(cval!=null)
  document.cookie= name + "="+cval+";expires="+exp.toGMTString();
}
//删除cookies（有作用域的）
function delCookie(name){
var exp = new Date();
var name = "access_token";
exp.setTime(exp.getTime() - 1);
var cval=getCookie(name);
if(cval!=null){
let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)
document.cookie= name + "='';expires="+exp.toGMTString()+";domain="+hostname+";path=/";
}

} 
//使用示例
setCookie('username','Darren',30)
alert(getCookie("username"));