datalist elementoption elements.interface HTMLDataListElement : HTMLElement {
  readonly attribute HTMLCollection options;
};
   The datalist element represents a set of
  option elements that represent predefined options for
  other controls. The contents of the element represents fallback
  content for legacy user agents, intermixed with option
  elements that represent the predefined options. In the rendering,
  the datalist element represents
  nothing and it, along with its children, should
  be hidden.
The datalist element is hooked up to an
  input element using the list attribute on the
  input element.
Each option element that is a descendant of the
  datalist element, that is not disabled, and whose value is a string that isn't the
  empty string, represents a suggestion. Each suggestion has a value and a label.
  
optionsReturns an HTMLCollection of the options elements of the table.
The options
  IDL attribute must return an HTMLCollection rooted at
  the datalist node, whose filter matches
  option elements.
Constraint validation: If an element has a
  datalist element ancestor, it is barred from
  constraint validation.