text = new Array(2);

text[0] = "<a target='_blank' rel='nofollow' class='mainlevel-nav' href = 'http://peerfly.com/x/0/3604/32864/'>Free IPhone5</a>";
text[1] = "<a target='_blank' rel='nofollow' class='mainlevel-nav' href = 'http://peerfly.com/x/0/3674/32864/'>Free Dell XPS</a>";

index = Math.floor(Math.random() * text.length);
document.write(text[index]);