How to focus first input when navigating multi-step form?

[danderson421]

What's the best way to focus on the first input within the section after moving from section to section? Currently, the focus stays on the button used to move from section to section (previous/next).

https://codepen.io/danderson421/pen/dyBmyZV?editors=101

What kind of issue is this? (put 'x' between the square brackets)

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  Provide working code, starting from http://codepen.io/marcandre/pen/jqbzyN?editors=101.
  We monitor the tag parsley.js.

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