SpeechGrammarList.addFromString

The addFromString() method of the SpeechGrammarList interface takes a grammar present in a specific DOMString within the code base (e.g. stored in a variable) and adds it to the SpeechGrammarList as a new SpeechGrammar object.

Syntax

speechGrammarListInstance.addFromString(string,weight);

Returns

Void.

Parameters

string

A DOMString representing the grammar to be added.

weight Optional

A float representing the weight of the grammar relative to other grammars present in the SpeechGrammarList. The weight means the importance of this grammar, or the likelihood that it will be recognised by the speech recognition service. The value can be between 0.0 and 1.0; If not specified, the default used is 1.0.

Examples

var grammar = '#JSGF V1.0; grammar colors; public <color> = aqua | azure | beige | bisque | black | blue | brown | chocolate | coral | crimson | cyan | fuchsia | ghostwhite | gold | goldenrod | gray | green | indigo | ivory | khaki | lavender | lime | linen | magenta | maroon | moccasin | navy | olive | orange | orchid | peru | pink | plum | purple | red | salmon | sienna | silver | snow | tan | teal | thistle | tomato | turquoise | violet | white | yellow ;'
var recognition = new SpeechRecognition();
var speechRecognitionList = new SpeechGrammarList();
speechRecognitionList.addFromString(grammar, 1);
recognition.grammars = speechRecognitionList;

Specifications

Specification	Status	Comment
Web Speech API The definition of 'addFromString()' in that specification.	Draft

Browser compatibility

• [1] Speech recognition interfaces are currently prefixed on Chrome, so you'll need to prefix interface names appropriately, e.g. webkitSpeechRecognition; You'll also need to serve your code through a web server for recognition to work.
• [2] Can be enabled via the media.webspeech.recognition.enable flag in about:config, although note that currently speech recognition won't work on Desktop Firefox — it will be properly exposed soon, once the required internal permissions are sorted out.

Firefox OS permissions

To use speech recognition in an app, you need to specify the following permissions in your manifest:

"permissions": {
  "audio-capture" : {
    "description" : "Audio capture"
  },
  "speech-recognition" : {
    "description" : "Speech recognition"
  }
}

You also need a privileged app, so you need to include this as well:

  "type": "privileged"

See also

• Web Speech API