"introduction to " or "introduction of "? I want to say, "Please give a brief introduction ____ your program", with prep. should I use?

"in the website" or "on the website", which is correct?

My Poor Nose Swimming is my favorite sport, and I'm taking a free-style course this semester. I go swimming three times a week. My trouble is each time I swim I would keep sneezing and get a stuffy nose for the whole evening since October. My doctor told me I've got allergic rhinitis, and I should try to avoid exposing my nose to the anaphylactogen, which means I should stop swimming. I cannot accept this! Trying my best to find other reasons for the allergy. Any changes in me in the recent two months? Any new food or drink taken? But the doc said they've got nothing to do with my allergy. I've been swimming for so many years and never felt any trouble with my nose. Then the change might be the new style I'm learning. My experiment yesterday proved that, in which I tried breaststrok as three month before and so no water got into my nose as they did when I'm practicing free-style. And the sneezing and stuffy nose didn't occur. Shall I give up free-style for sake of my nose?

"Travelling" or "Traveling" Which one is the correct spelling? Or both are OK?

Swimming Championship I'm quite pleased with the experience of watching the World Swimming Championship in this summer. Not only that it makes me feel cool seeing the blue pool, but also I'm proud of the gold medals and world record made by my fellow countrymen. And I learnt that I don't need to push myself too much to learn bilateral breathing in freestyle, for many first-class swimmers just breathe to one side.