HTMLFormElement or SubmitEvent to get the values from
a mapping between the input's name and their values. The type of value is determined as so:
<input type="checkbox">: boolean or null if indeterminate<input type="datetime-local">: Date or null if none is entered<input type="file">: FileList<input type="number">: number<input type="range">: number<input type="radio">: string - The value of the selected radio button. If none are selected, this will be an
empty string. This reflects the behaviour of RadioNodeList.string
Takes in a form element or submit event and returns a mapping between the input's name and their values
If using a
SubmitEvent, thenameandvalueof theHTMLButtonElementused to submit the form will be included.