There is no difference. They are often called UV Haze filters and they don't filter out a lot of UV. UV filters are really just used for protection most of the time. If you really wanted to filter the UV light you might want to use a UV blocking filter, which you probably don't need to worry about yet.
There are three schools of though on this topic.
1. Always use a filter for protection. If you take this route you should probably get a high quality filter like a B+W MRC.
2. Never use a filter. UV filters DO NOT enhance image quality, in fact they tend to degrade it. If you choose not to use filters you should use a hood and you need to train yourself to always protect the front element from harm.
3. Use filters only when it's called for, so you would put one on if you're shooting under adverse conditions like rain, snow or surf.