JavaScript: Hvad er der galt her?!

Hvad er der galt her?!

<script language=javascript>
var pictures = new Array("\thumbs\tn_01s.jpg", "\thumbs\tn_02s.jpg", "\thumbs\tn_03s.jpg", "\thumbs\tn_04s.jpg", "\thumbs\tn_05s.jpg", "\thumbs\tn_06s.jpg", "\thumbs\tn_07s.jpg", "\thumbs\tn_08s.jpg", "\thumbs\tn_007S.jpg", "\thumbs\tn_027S.jpg", "\thumbs\tn_F1000003ST.jpg", "\thumbs\tn_F1000004.jpg");
var alt = new Array("alt1", "alt2", "alt3", "alt4", "alt5", "alt6", "alt7", "alt8", "alt9", "alt10", "alt11", "alt12",);
var randomindex = Math.round(Math.random()*(pictures.length-1));
var img = pictures[randomindex];
var alttxt = alt[randomindex];
document.write("<img src=\"" + img + "\" ALT=\"" + alttxt + "\">");
</script>