function setCookie(c_name,value,expiredays)
{var exdate=new Date();exdate.setDate(exdate.getDate()+expiredays);
document.cookie=c_name+ "=" +escape(value)+
((expiredays==null) ? "" : ";expires="+exdate.toGMTString());
}	 

 function getCookie(c_name)
{
if (document.cookie.length> 0 )
  {
  c_start=document.cookie.indexOf(c_name + "=");
  if (c_start!=- 1 )
    { 
    c_start=c_start + c_name.length+ 1 ; 
    c_end=document.cookie.indexOf(";",c_start);
    if (c_end==- 1 ) c_end=document.cookie.length;
    return unescape(document.cookie.substring(c_start,c_end));
    } 
  }
return "";
}	  



function checkCookie()
{
username=getCookie('username');
if (username!=null && username!="")
{
alert('Welcome again '+username+'!');
}
else 
{
username=prompt('Please enter your name:',"");
if (username!=null && username!="")
{
setCookie('username',username, 365 );
} 
}
}