/*
 * Creates a cookie.
 */
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=/";
}

/*
 * Reads a cookie.
 */
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 unescape(c.substring( nameEQ.length, c.length ));
        }
    }
    return "";
}

/*
 * Erases a cookie.
 */
function eraseCookie ( name ) {
    createCookie( name, "", -1 );
}