function getCookie( name ) {
    var start = document.cookie.indexOf( name + "=" );
    var len = start + name.length + 1;
    if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) ) {
    return null;
    }
    if ( start == -1 ) return null;
    var end = document.cookie.indexOf( ';', len );
    if ( end == -1 ) end = document.cookie.length;
    return unescape( document.cookie.substring( len, end ) );
}

// Esta funcion extrae los valores de la url
function getValues(){

    var urlEnd = document.URL.indexOf('?');
    var values = new Array();
    var names;
    
    if (urlEnd != -1){
    var params = document.URL.substring(urlEnd+1, document.URL.length).split('&');
    
    for(i=0; i<params.length; i++) {
        names = params[i].split('=');
        values[names[0]] = names[1];
    }
}
return values;
}