added hello world title with js

this here is to just add "Hello World" as a title on index.html
while this works, you should always keep in mind that a lot of times you don't have control over you javascript files, for example if this file will be concatenated with others and placed in the head it won't work. And that's assuming you have some control over you dependencies.

So yeah, you should always do `$(function() { ... })` or equivalent `$(document).ready(function () { ... })`