Came a cropper with this today. Wired up a $.ajax() event to my [button] thinking that all should be well.

Couldn't understand why the ajax call was terminating BEFORE the code on the server side was being called, even though the server side code was actually being called!

Should have known this, but [button] behaves as a Submit button under all browsers except IE, if you don't mark the "type" attribute.

See http://www.w3schools.com/tags/tag_button.asp for more info