cookie manipulation

var cvalue=""; 
var cname='hl'; 
function RndNum(n){
   var rnd="";
   for(var i=0;i<n;i++)
      rnd+=Math.floor(Math.random()*10);
   return rnd;
}
cvalue = RndNum (5 );

function setCookie(cname,value) //写cookie
{
   /* var Days = 0;
    var exp = new Date();
    exp.setTime(exp.getTime() + Days*24*60*60*1000);*/
   document.cookie = cname + "="+ escape (value)/* + ";expires=" + exp.toGMTString();*/
}

function getCookie(name) //读cookie
{
   var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
   if(arr=document.cookie.match(reg))
      return unescape(arr[2]);
   else
      return null;
}

if(getCookie(cname)==null){
   setCookie(cname,cvalue);
}

console.log(getCookie(cname));

The cookie operation is used in the project. After a simple toss, it is OK.