Upload control and MediaType attribute

8.1.6 The upload Element
  ....
  mediatype 
    List of suggested media types


How are multiple media types specified?

  <upload mediatype="text/plain text/html">
or 

  <upload mediatype="text/plain,text/html">

or
  ....

Most of the implementation (I guess) will assume a comma separated list
of media-types. But in any case I think the spec should clearly state
this.

Regards