<i><a href="cat.html">Кошки</a></i>
var myTxt = new Array(
"1111 111 111 11 111 111",
"2 22 22 2222 2222 22",
"333 33 33333 3333 333 333",
"4 444 444 4444 4444 44444",
"<a href="cat.html">Кошки</a>"
);
randnm=Math.round(Math.random()*(myTxt.length-1));
document.getElementById("header").innerHTML = myTxt[randnm];