why does this happend when i try to put this random text jav

i put this javascrtip code in my portal but it wont show nothing
what is the problem ???

<script type="text/javascript">
<!--
var text = new Array ();
text[1] = "Random text 1";
text[2] = "Random text 2";
text[3] = "Random text 3";

var i = Math.round(3*Math.random());

document.write(text[i]);

//-->
</script>