The data attribute (for select elements)

• Fill a select element with options from an external XML document.

• MIME media type of the external document must be application/xml or some XML type.

• The document contains a single select element in the XHTML namespace containing option elements.

<form>
 <label>Choose the species:
    <select name="species" data='examples/species.xhtml'></select>
  </label>
 <label><input type="submit" value="Send data" /></label></p>
</form>