Java Script to Read, Write, and Delete cookies

function writeCookie(name,value,days){
var expires = "";

if(days){
 var date = new Date();
 date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
 expires = "; expires="+date.toGMTString();
}

document.cookie = name + "=" + value + expires + "; path=/";
}

function readCookie(name){
 var searchName = name + "=";

 var cookies = document.cookie.split(';')

for(var i = 0;i < cookies.length;i++){

   var c = cookies[i];

  alert("c:" + c);

   while(c.charAt(0) == ' '){
    alert("2:" + c);
    c = c.substring(1,c.length);
   }

  if(c.indexOf(searchName) == 0){
     alert("1:"+ c);
     return c.substring(searchName.length, c.length);
  }

 }
return null;
}

function eraseCookie(name) {
 writeCookie(name,"",-1);
}