//gets a cookie with a given name
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 null
}

//sets a cookie with a name, value, and number of days to expire
function setCookie(c_name,value,expiredays)
{
	var exdate=new Date()
	exdate.setTime(exdate.getTime()+(expiredays*24*3600*1000))
	document.cookie=c_name+ "=" +escape(value)+
	((expiredays==null) ? "" : "; expires="+exdate)
}

//function checks if cookie has been set
function checkCookie(c_name)
{
	cookievalue=getCookie(c_name)
	if (cookievalue!=null)
	{
		return true;
	}
	else 
	{
		return false;
	}
}

//clears a cookie with a given name by setting expire date to yesterday
function clearCookie(c_name)
{
	setCookie(c_name, '', -1);
}