var textnumber = 2;
var randomnumber = Math.random() ;
var rand1 = Math.round( (textnumber-1) * randomnumber) + 1 ;
text = new Array
text[1] = '
ciberbanner.com intercambio de banners'
text[2] = '
'
var mytext = text[rand1]
document.write(text[rand1]);