function create_cookie( 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 read_cookie( name ) 
{
	var name_eq = 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( name_eq ) == 0 ) return c.substring( name_eq.length, c.length );
	}
	
	return null;
}

function erase_cookie ( name ) 
{
	create_cookie( name, "", -1 );
}