Assuming what you want to accomplish on a customer site.
Array/String "", .
$(document).ready(function () {
var RandComment= ["First Random Comment","Second Random Comment","Third Random Comment"]
$("#btnSubmit").click(function () {
var pickRandomComment = RandComment[parseInt(Math.random() * RandComment.length-1)];
$("#txtCommentBox").val(pickRandomComment);
});
});