Thanks a lot. Would you explain why I was getting such alert msg?

Now working well. Cool!

Glad it's working. Eric's the 'Code Man'!

Eric to the rescue again!

What your seeing is actually a browser issue. Since there was no specific action tied to the button the browser defaults to submit. The other way around would be to use the <input type="button" value="Next" /> instead. You need to specify the action to it as in how the form builder does.
<input type="submit" value="Submit" />