function createCookie( name, value, days )
{
	if ( days )
    {
		var date = new Date();
		date.setTime( date.getTime() + ( days * 24 * 60 * 60 * 1000 ) );
		var expires = "; expires=" + date.toGMTString();
	}
	else
    {
        var expires = "";
    }

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

function readCookie( name )
{
	var nameEQ = name + '=';
	var ca = document.cookie.split( ';' );

	for ( var i = 0; i < ca.length; i++ )
    {
		var c = ca[ i ];
		while ( c.charAt( 0 ) == ' ' )
        {
            c = c.substring( 1, c.length );
        }

        if ( c.indexOf( nameEQ ) == 0 )
        {
            return c.substring( nameEQ.length, c.length );
        }
	}
	return null;
}

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