--- a/midi/specification.html	Wed May 23 15:17:48 2012 +0300
+++ b/midi/specification.html	Wed May 23 15:42:00 2012 +0300
@@ -237,13 +237,61 @@
           </ol>
         </dd>
         <dt><a>MIDIMessage</a> createMIDIMessage(short status, Uint8Array
-                                                  data, long? timestamp)</dt>
+                                    data, long? timestamp, short? channel)</dt>
         <dd>
           <p>
             Creates and returns a new <code><a>MIDIMessage</a></code> according
             to the specified parameters.
           </p>
-<!-- TODO: Specify the steps the UA is required to take. -->
+
+          <p>
+            When the
+            <dfn id="midiaccess-create-midi-message"><code>createMIDIMessage()</code></dfn>
+            is invoked, the user agent MUST run the following steps:
+          </p>
+
+          <ol>
+            <li>
+              <p>
+                Let <var>status</var> be the <code>short</code> argument.
+              </p>
+            </li>
+
+            <li>
+              <p>
+                Let <var>data</var> be the <code>Uint8Array</code> argument.
+              </p>
+            </li>
+
+            <li>
+              <p>
+                Let <var>timestamp</var> be the
+                <code>long</code> argument, if not null. Else let
+                <var>timestamp</var> be the current time as the amount of
+                milliseconds from the UNIX Epoch.
+              </p>
+            </li>
+
+            <li>
+              <p>
+                Let <var>channel</var> be the <code>short</code> argument,
+                if not null. Else let <var>channel</var> be zero.
+              </p>
+            </li>
+
+            <li>
+              <p>
+                Let <var>message</var> be a new <code><a>MIDIMessage</a></code>
+                with <var>status</var>, <var>data</var>, <var>timestamp</var>
+                and <var>channel</var> assigned to their corresponding
+                properties of the <var>message</var>.
+              </p>
+            </li>
+
+            <li>
+              <p>Return <var>message</var></p>
+            </li>
+          </ol>
         </dd>
       </dl>
     </section>