I have a form composed of two form steps, first of which is mandatory, and the second is optional. For example, I want the submit button appears/disappears depending on a selection of a field (for example, a checkbox status). For example, if I check the checkbox on the first form step, the submit button will appear on the firt form step, and the next form button disappears. However, if I uncheck the checkbox, the next form step button appears, and the submit button on the first form step will be moved to the second form step.

Any third party library?