Jump to form field on button click

I want to create buttons that allow me to jump to specific fields. The documentation for the form plugin has the info below, but I don’t understand how to add it to the button OnClick event:

GOTOFIELD( field, form object )
Jumps to a field in the form.

field, integer number corresponding to the number component in the field name or the field name (required parameter).
form object, an optional parameter corresponding to the form where the field is.

In the context of the equation, call the operation passing only the number component in the field name,
Ex. GOTOFIELD(2);
But if the operation is called from the onclick event of a button, the form object is required,
Ex. GOTOFIELD(“fieldname2”, this.form);

Any help?

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