$(document).prop('title', 'test');
This is simply a JQuery wrapper for:
document.title="test";
To add a > periodically you can do:
function changeTitle() {
var title = $(document).prop('title');
if (title.indexOf('>>>') == -1) {
setTimeout(changeTitle, 3000);
$(document).prop('title', '>'+title);
}
}
changeTitle();