When I try this (hand coding it in the developer tools) this works fine. So my first recommendation would be to examine the html that gets rendered in the browser to ensure that it’s being rendered correctly. Verify that the onclick attribute is being rendered correctly.
What I do see (but am not directly aware of any adverse implications) is that you have these buttons defined as type="submit", when they are explicitly not going to submit the form in which they are enclosed. I would also recommend changing them to type="button". (Or, replace the input elements with button elements.)