Definition
Web Speech API defines SpeechGrammarList
// The object representing a speech grammar collection. This interface has been deprecated and exists in this spec for the sole purpose of maintaining backwards compatibility.
[Exposed=Window]
interface SpeechGrammarList {
constructor();
readonly attribute unsigned long length;
getter SpeechGrammar item(unsigned long index);
undefined addFromURI(DOMString src,
optional float weight = 1.0);
undefined addFromString(DOMString string,
optional float weight = 1.0);
};