If you look at the way JQM treats text, you will notice it has text-overflow set to ellipsis on most elements. The reason is good, but it can be annoying. If you have long text, your header will be huge, so instead of a huge header, it adds ellipsis. To prevent this add style="white-space:normal" to your <h1> and it should be fine.
Here is a demo. You can mess around with it in JSFiddle.