codice:
var _links = new Array( );

_links[_links.length] = "http://www.sito1.com/";
_links[_links.length] = "http://www.sito2.com/";
_links[_links.length] = "http://www.sito3.com/";
_links[_links.length] = "http://www.sitoN.com/";



var _rndLinkId   = Math.floor( Math.random( ) * _links.length );
var _rndLinkHref = _links[ _rndLinkId ];

window.location.replace( _rndLinkHref );