<p>

<em><b>failure</b></em>: Let <var>error</var> be a new

{{DOMException}}. This exception's .name should be

denied the application from creating a MIDIAccess instance

with the requested options, or if the error is the result of

<var>document</var> not being [=allowed to use=] the feature,

{{requestMIDIAccess()}}, if this member is set to true, but

[=System Exclusive=] support is denied (either by policy or by

user action), the access request will fail with a

allowed), the system will throw exceptions if the user tries to

send [=System Exclusive=] messages, and will silently mask out

any [=System Exclusive=] messages received on the port.

{{requestMIDIAccess()}}, if this member is set to true, but

software synthesizer support is denied (either by policy or by

user action), the access request will fail with a

system should not include any software synthesizers in the

{{MIDIAccess}} exposure of available ports.

</p>